HTML5 placeholder polyfill

HTML5 placeholder polyfill.js

// Version 1.0 - 2012/07/06, by Sten Hougaard, http://twitter.com/netsi1964 
// Handles browsers which do not support HTML5 placeholder attribute
// Will setup code which emulates the HTML5 placeholder feature
// Require jQuery 1.7.1+
// Defaults to CSS selector which hits any element using "placeholder"
// USE: placeholderPolyfill([selector])
function placeholderPolyfill(sSelector) {
	var bSupportsPlaceholder = 'placeholder' in document.createElement('input');
	if (!!bSupportsPlaceholder) return;
	jQuery((typeof sSelector!='undefined') ? sSelector : '[placeholder]').each(function() {
		var $this = jQuery(this);
		if (!bSupportsPlaceholder) {
			var placeholderValue = $this.attr('placeholder');
			$this.val(placeholderValue);
			$this.on('focus', function() {
				if ($this.val()===placeholderValue) $this.val('');
			}).on('blur', function() {
				if ($this.val()==='') $this.val(placeholderValue);
			});
		};
	});
};