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357 lines
11 KiB
Markdown
357 lines
11 KiB
Markdown
title: Common Variables
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summary: Some of the common variables and methods your templates can use, including Menu, SiteConfig, and more.
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# Common Variables
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The page below describes a few of common variables and methods you'll see in a SilverStripe template. This is not an
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exhaustive list. From your template you can call any method, database field, or relation on the object which is
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currently in scope as well as its' subclasses or extensions.
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Knowing what methods you can call can be tricky, but the first step is to understand the scope you're in. Scope is
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explained in more detail on the [syntax](syntax#scope) page. Many of the methods listed below can be called from any
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scope, and you can specify additional static methods to be available globally in templates by implementing the
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[api:TemplateGlobalProvider] interface.
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<div class="notice" markdown="1">
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Want a quick way of knowing what scope you're in? Try putting `$ClassName` in your template. You should see a string
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such as `Page` of the object that's in scope. The methods you can call on that object then are any functions, database
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properties or relations on the `Page` class, `PageController` class as well as anything from their subclasses **or**
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extensions.
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</div>
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Outputting these variables is only the start, if you want to format or manipulate them before adding them to the template
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have a read of the [Formating, Modifying and Casting Variables](casting) documentation.
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<div class="alert" markdown="1">
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Some of the following only apply when you have the `CMS` module installed. If you're using the `Framework` alone, this
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functionality may not be included.
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</div>
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## Base Tag
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:::ss
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<head>
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<% base_tag %>
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..
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</head>
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The `<% base_tag %>` placeholder is replaced with the HTML base element. Relative links within a document (such as <img
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src="someimage.jpg" />) will become relative to the URI specified in the base tag. This ensures the browser knows where
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to locate your site’s images and css files.
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It renders in the template as `<base href="http://www.yoursite.com" /><!--[if lte IE 6]></base><![endif]-->`
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<div class="alert" markdown="1">
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A `<% base_tag %>` is nearly always required or assumed by SilverStripe to exist.
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</div>
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## CurrentMember
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Returns the currently logged in [api:Member] instance, if there is one logged in.
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:::ss
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<% if $CurrentMember %>
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Welcome Back, $CurrentMember.FirstName
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<% end_if %>
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## Title and Menu Title
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:::ss
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$Title
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$MenuTitle
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Most objects within SilverStripe will respond to `$Title` (i.e they should have a `Title` database field or at least a
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`getTitle()` method).
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The CMS module in particular provides two fields to label a page: `Title` and `MenuTitle`. `Title` is the title
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displayed on the web page, while `MenuTitle` can be a shorter version suitable for size-constrained menus.
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<div class="notice" markdown="1">
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If `MenuTitle` is left blank by the CMS author, it'll just default to the value in `Title`.
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</div>
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## Page Content
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:::ss
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$Content
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It returns the database content of the `Content` property. With the CMS Module, this is the value of the WYSIWYG editor
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but it is also the standard for any object that has a body of content to output.
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<div class="info" markdown="1">
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Please note that this database content can be `versioned`, meaning that draft content edited in the CMS can be different
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from published content shown to your website visitors. In templates, you don't need to worry about this distinction.
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The `$Content` variable contains the published content by default,and only preview draft content if explicitly
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requested (e.g. by the "preview" feature in the CMS) (see the [versioning documentation](/../model/versioning) for
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more details).
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</div>
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### SiteConfig: Global settings
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<div class="notice" markdown="1">
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`SiteConfig` is a module that is bundled with the `CMS`. If you wish to include `SiteConfig` in your framework only
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web pages. You'll need to install it via `composer`.
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</div>
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:::ss
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$SiteConfig.Title
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The [SiteConfig](../configuration/siteconfig) object allows content authors to modify global data in the CMS, rather
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than PHP code. By default, this includes a Website title and a Tagline.
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`SiteConfig` can be extended to hold other data, for example a logo image which can be uploaded through the CMS or
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global content such as your footer content.
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## Meta Tags
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The `$MetaTags` placeholder in a template returns a segment of HTML appropriate for putting into the `<head>` tag. It
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will set up title, keywords and description meta-tags, based on the CMS content and is editable in the 'Meta-data' tab
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on a per-page basis.
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<div class="notice" markdown="1">
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If you don’t want to include the title tag use `$MetaTags(false)`.
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</div>
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By default `$MetaTags` renders:
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:::ss
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<title>Title of the Page</title>
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<meta name="generator" http-equiv="generator" content="SilverStripe 3.0" />
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<meta http-equiv="Content-type" content="text/html; charset=utf-8" />
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`$MetaTags(false)` will render
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:::ss
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<meta name="generator" http-equiv="generator" content="SilverStripe 3.0" />
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<meta http-equiv="Content-type" content="text/html; charset=utf-8" />
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If using `$MetaTags(false)` we can provide a more custom `title`.
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:::ss
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$MetaTags(false)
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<title>$Title - Bob's Fantasy Football</title>
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## Links
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:::ss
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<a href="$Link">..</a>
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All objects that could be accessible in SilverStripe should define a `Link` method and an `AbsoluteLink` method. Link
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returns the relative URL for the object and `AbsoluteLink` outputs your full website address along with the relative
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link.
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:::ss
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$Link
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<!-- returns /about-us/offices/ -->
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$AbsoluteLink
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<!-- returns http://yoursite.com/about-us/offices/ -->
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### Linking Modes
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:::ss
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$isSection
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$isCurrent
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When looping over a list of `SiteTree` instances through a `<% loop $Menu %>` or `<% loop $Children %>`, `$isSection` and `$isCurrent`
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will return true or false based on page being looped over relative to the currently viewed page.
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For instance, to only show the menu item linked if it's the current one:
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:::ss
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<% if $isCurrent %>
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$Title
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<% else %>
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<a href="$Link">$Title</a>
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<% end_if %>
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An example for checking for `current` or `section` is as follows:
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:::ss
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<a class="<% if $isCurrent %>current<% else_if $isSection %>section<% end_if %>" href="$Link">$MenuTitle</a>
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**Additional Utility Method**
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* `$InSection(page-url)`: This if block will pass if we're currently on the page-url page or one of its children.
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:::ss
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<% if $InSection(about-us) %>
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<p>You are viewing the about us section</p>
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<% end_if %>
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### URLSegment
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This returns the part of the URL of the page you're currently on. For example on the `/about-us/offices/` web page the
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`URLSegment` will be `offices`. `URLSegment` cannot be used to generate a link since it does not output the full path.
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It can be used within templates to generate anchors or other CSS classes.
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:::ss
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<div id="section-$URLSegment">
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</div>
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<!-- returns <div id="section-offices"> -->
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## ClassName
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Returns the class of the current object in [scope](syntax#scope) such as `Page` or `HomePage`. The `$ClassName` can be
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handy for a number of uses. A common use case is to add to your `<body>` tag to influence CSS styles and JavaScript
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behavior based on the page type used:
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:::ss
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<body class="$ClassName">
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<!-- returns <body class="HomePage">, <body class="BlogPage"> -->
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## Children Loops
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:::ss
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<% loop $Children %>
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<% end_loop %>
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Will loop over all Children records of the current object context. Children are pages that sit under the current page in
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the `CMS` or a custom list of data. This originates in the `Versioned` extension's `getChildren` method.
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<div class="alert" markdown="1">
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For doing your website navigation most likely you'll want to use `$Menu` since its independent of the page
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context.
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</div>
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### ChildrenOf
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:::ss
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<% loop $ChildrenOf(<my-page-url>) %>
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<% end_loop %>
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Will create a list of the children of the given page, as identified by its `URLSegment` value. This can come in handy
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because it's not dependent on the context of the current page. For example, it would allow you to list all staff member
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pages underneath a "staff" holder on any page, regardless if its on the top level or elsewhere.
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### AllChildren
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Content authors have the ability to hide pages from menus by un-selecting the `ShowInMenus` checkbox within the CMS.
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This option will be honored by `<% loop $Children %>` and `<% loop $Menu %>` however if you want to ignore the user
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preference, `AllChildren` does not filter by `ShowInMenus`.
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:::ss
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<% loop $AllChildren %>
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...
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<% end_loop %>
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### Menu Loops
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:::ss
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<% loop $Menu(1) %>
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...
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<% end_loop %>
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`$Menu(1)` returns the top-level menu of the website. You can also create a sub-menu using `$Menu(2)`, and so forth.
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<div class="notice" markdown="1">
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Pages with the `ShowInMenus` property set to `false` will be filtered out.
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</div>
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## Access to a specific Page
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:::ss
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<% with $Page(my-page) %>
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$Title
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<% end_with %>
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Page will return a single page from site, looking it up by URL.
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## Access to Parent and Level Pages
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### Level
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:::ss
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<% with $Level(1) %>
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$Title
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<% end_with %>
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Will return a page in the current path, at the level specified by the numbers. It is based on the current page context,
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looking back through its parent pages. `Level(1)` being the top most level.
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For example, imagine you're on the "bob marley" page, which is three levels in: "about us > staff > bob marley".
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* `$Level(1).Title` would return "about us"
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* `$Level(2).Title` would return "staff"
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* `$Level(3).Title` would return "bob marley"
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### Parent
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:::ss
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<!-- given we're on 'Bob Marley' in "about us > staff > bob marley" -->
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$Parent.Title
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<!-- returns 'staff' -->
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$Parent.Parent.Title
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<!-- returns 'about us' -->
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## Navigating Scope
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See [scope](syntax#scope).
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## Breadcrumbs
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Breadcrumbs are the path of pages which need to be taken to reach the current page, and can be a great navigation aid
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for website users.
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While you can achieve breadcrumbs through the `$Level(<level>)` control manually, there's a nicer shortcut: The
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`$Breadcrumbs` variable.
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:::ss
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$Breadcrumbs
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By default, it uses the template defined in `cms/templates/BreadcrumbsTemplate.ss`
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:::ss
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<% if $Pages %>
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<% loop $Pages %>
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<% if $Last %>$Title.XML<% else %><a href="$Link">$MenuTitle.XML</a> »<% end_if %>
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<% end_loop %>
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<% end_if %>
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<div class="info" markdown="1">
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To customise the markup that the `$Breadcrumbs` generates, copy `cms/templates/BreadcrumbsTemplate.ss` to
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`mysite/templates/BreadcrumbsTemplate.ss`, modify the newly copied template and flush your SilverStripe cache.
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</div>
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## Forms
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:::ss
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$Form
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A page will normally contain some content and potentially a form of some kind. For example, the log-in page has a the
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SilverStripe log-in form. If you are on such a page, the `$Form` variable will contain the HTML content of the form.
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Placing it just below `$Content` is a good default.
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You can add your own forms by implementing new form instances (see the [Forms tutorial](/tutorials/forms)).
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## Related
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* [Casting and Formating Variables](casting)
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* [Template Inheritance](template_inheritance)
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## API Documentation
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* [api:ContentController]: The main controller responsible for handling pages.
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* [api:Controller]: Generic controller (not specific to pages.)
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* [api:DataObject]: Underlying model class for page objects.
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* [api:ViewableData]: Underlying object class for pretty much anything displayable.
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