6.9 KiB
#Placeholders.js - An HTML5 placeholder attribute polyfill
Placeholders.js is a polyfill (or shim, or whatever you like to call it) for the HTML5 placeholder attribute, as defined in the HTML5 draft specification. Placeholder attributes are valid on input
elements of various types and textarea
elements.
Placeholders.js is licensed under the MIT License. See the unminified file for the full license text.
##Features
-
Works on both
input
andtextarea
elements -
Works by finding
placeholder
attributes on elements, so there's no need to call it repeatedly for every element. Just add the placeholder attribute as if it were supported natively. -
Simulates native styles for the placeholders but keeps any custom styles you've defined on the elements
-
Placeholder values are not submitted as form data if the element is part of a form
-
Works for elements that are added to the DOM after the page has loaded, and also for elements whose placeholder value changes after the page has loaded
-
Works properly for
input
elements of thepassword
type in all browsers except Internet Explorer 8 and below, in which the placeholder appears as masked text -
Wide range of browsers supported, including IE6
-
No dependencies (so no need to include jQuery, unlike most placeholder polyfill scripts)
-
All of the above in just 5kB when minified, and about 1kB when gzipped!
##How do I use it?
Placeholders.js is designed to replicate native placeholder attribute functionality as best as it can. To get it working, simply define placeholders on your input
or textarea
elements as usual:
<input type="text" placeholder="Sample text">
<textarea placeholder="My placeholder"></textarea>
Just include the script and call the init
method whenever you're ready. I suggest calling it in a DOM ready event listener of some description:
Placeholders.init();
That's all there is to it! Browsers that alreay support the placeholder attribute natively will be unaffected. They continue to use their built-in method.
##The init
method
The init
method is all that you need to call to get the polyfill working. It accepts one argument, settings
. The settings
argument should be an object. It currently supports two properties:
-
live
- Iftrue
, this option causes the polyfill to apply to allinput
andtextarea
elements, both now and in the future. This means if you insert a new element into the DOM, its placeholder attribute will function as expected. If the value of a placeholder attribute is modified by code sometime after theinit
method has executed,live
will cause the changes to be reflected. If thelive
option isfalse
, or not specified, the new element would not display its placeholder, and modified placeholder values would not function correctly. Default:false
. -
hideOnFocus
- Iftrue
, this option will cause the placeholder to disappear when the element receives focus. Iffalse
, or not specified, the placeholder will disappear when some input is entered into the element. Default:false
. -
className
- A custom class name that will be added to each element to which the polyfill applies. Default:placeholderspolyfill
. -
textColor
- The default color of the placeholder text. Default:#999
(gray). -
styleImportant
- Boolean flag that specifies whether or not the!important
directive should be added to the polyfill styles. Default:true
.
Here's an example call to the init
method:
Placeholders.init({
live: true, //Apply to future and modified elements too
hideOnFocus: true //Hide the placeholder when the element receives focus
});
##The refresh
method
The refresh
method can be called at any time to update the placeholders defined on elements, and detect any elements recently added to the DOM. You only need to use the refresh
method if the live
argument was set to false
when you called init
.
Placeholders.refresh();
##Known Issues
-
When applying a placeholder to an
input
element of typepassword
, the default "hidden" character is used instead of plain text in Internet Explorer 8 and below. Password inputs now work correctly in Internet Explorer 9. -
Because the polyfill uses the
value
attribute to display the placeholder, users will be unable to enter the placeholder value as valid input. -
(When the
hideOnFocus
option isfalse
) The cursor position can currently be changed after focus, so you can insert characters in the middle of the placeholder value (causing the placeholder not to hide). -
The placeholder text cannot be styled. The ability to do so is currently non-standard, but is present in WebKit (with the
::-webkit-input-placeholder
pseudoelement), Firefox 4+ (with the:-moz-placeholder
pseudoclass) and Internet Explorer 10 (with the:-ms-input-placeholder
pseudoclass). This feature will not be added to the polyfill until some standard is defined.
##Supported Browsers
Placeholders.js aims to support the widest range of browsers possible. The idea is that you will be able to use the native placeholder
attribute along with Placeholders.js and your users on any platform will get the same experience. This table will be updated as and when further browsers are tested. Mobile browser testing is a big one that's high on the list. Currently tested and working in the following browsers on (where applicable) both Windows 7 and CentOS 6:
- Internet Explorer 6 - 9 (with Placeholders.js)
- Firefox 1 - 3 (with Placeholders.js), 4+ (native)
- Opera 7 - 10 (with Placeholders.js), 11+ (native)
- Safari 3.2 (with Placeholders.js), 4+ (native)
- Chrome 4+ (native)
- Flock 1.0+ (with Placeholders.js)
- Konqueror 4.3 (with Placeholders.js)
- SeaMonkey 1+ (with Placeholders.js)
- Maxthon 1+ (with Placeholders.js)
- SlimBrowser 5 (with Placeholders.js)
- K-Meleon 0.7+ (with Placeholders.js)
Do you use some obscure browser that doesn't have native placeholder
attribute support? If so, please let me know so I can make sure Placeholders.js works with it.
##Contributors
Many thanks to @ioptics for asking me to write this in the first place. Also thanks to:
- @markcarlson for a major bug fix
- @ralgh for adding options to customize the polyfill styles
##Downloads
You can download the repository at various states from the tags page, or with the following links:
Current version (1.3) | 1.2.1 | 1.1 | 1.0