jquery/src/attributes.js

jQuery.fn.extend({
	attr: function( name, value ) {
		var options = name, isFunction = jQuery.isFunction( value );

		if ( typeof name === "string" ) {
			// Are we setting the attribute?
			if ( value === undefined ) {
				return this.length ?
					jQuery.attr( this[0], name ) :
					null;

			// Convert name, value params to options hash format
			} else {
				options = {};
				options[ name ] = value;
			}
		}

		// For each element...
		for ( var i = 0, l = this.length; i < l; i++ ) {
			var elem = this[i];

			// Set all the attributes
			for ( var prop in options ) {
				value = options[prop];

				if ( isFunction ) {
					value = value.call( elem, i );
				}

				jQuery.attr( elem, prop, value );
			}
		}

		return this;
	},

	hasClass: function( selector ) {
		return !!selector && this.is( "." + selector );
	},

	val: function( value ) {
		if ( value === undefined ) {
			var elem = this[0];

			if ( elem ) {
				if( jQuery.nodeName( elem, 'option' ) )
					return (elem.attributes.value || {}).specified ? elem.value : elem.text;
				
				// We need to handle select boxes special
				if ( jQuery.nodeName( elem, "select" ) ) {
					var index = elem.selectedIndex,
						values = [],
						options = elem.options,
						one = elem.type == "select-one";

					// Nothing was selected
					if ( index < 0 )
						return null;

					// Loop through all the selected options
					for ( var i = one ? index : 0, max = one ? index + 1 : options.length; i < max; i++ ) {
						var option = options[ i ];

						if ( option.selected ) {
							// Get the specifc value for the option
							value = jQuery(option).val();

							// We don't need an array for one selects
							if ( one )
								return value;

							// Multi-Selects return an array
							values.push( value );
						}
					}

					return values;				
				}

				// Everything else, we just grab the value
				return (elem.value || "").replace(/\r/g, "");

			}

			return undefined;
		}

		if ( typeof value === "number" )
			value += '';

		return this.each(function(){
			if ( this.nodeType != 1 )
				return;

			if ( jQuery.isArray(value) && /radio|checkbox/.test( this.type ) )
				this.checked = (jQuery.inArray(this.value, value) >= 0 ||
					jQuery.inArray(this.name, value) >= 0);

			else if ( jQuery.nodeName( this, "select" ) ) {
				var values = jQuery.makeArray(value);

				jQuery( "option", this ).each(function(){
					this.selected = (jQuery.inArray( this.value, values ) >= 0 ||
						jQuery.inArray( this.text, values ) >= 0);
				});

				if ( !values.length )
					this.selectedIndex = -1;

			} else
				this.value = value;
		});
	}
});

jQuery.each({
	removeAttr: function( name ) {
		jQuery.attr( this, name, "" );
		if (this.nodeType == 1)
			this.removeAttribute( name );
	},

	addClass: function( classNames ) {
		jQuery.className.add( this, classNames );
	},

	removeClass: function( classNames ) {
		jQuery.className.remove( this, classNames );
	},

	toggleClass: function( classNames, state ) {
		if( typeof state !== "boolean" )
			state = !jQuery.className.has( this, classNames );
		jQuery.className[ state ? "add" : "remove" ]( this, classNames );
	}
}, function(name, fn){
	jQuery.fn[ name ] = function(){
		return this.each( fn, arguments );
	};
});

jQuery.extend({
	className: {
		// internal only, use addClass("class")
		add: function( elem, classNames ) {
			jQuery.each((classNames || "").split(/\s+/), function(i, className){
				if ( elem.nodeType == 1 && !jQuery.className.has( elem.className, className ) )
					elem.className += (elem.className ? " " : "") + className;
			});
		},

		// internal only, use removeClass("class")
		remove: function( elem, classNames ) {
			if (elem.nodeType == 1)
				elem.className = classNames !== undefined ?
					jQuery.grep(elem.className.split(/\s+/), function(className){
						return !jQuery.className.has( classNames, className );
					}).join(" ") :
					"";
		},

		// internal only, use hasClass("class")
		has: function( elem, className ) {
			return elem && jQuery.inArray( className, (elem.className || elem).toString().split(/\s+/) ) > -1;
		}
	},

	attr: function( elem, name, value ) {
		// don't set attributes on text and comment nodes
		if (!elem || elem.nodeType == 3 || elem.nodeType == 8)
			return undefined;

		var notxml = !elem.tagName || !jQuery.isXMLDoc( elem ),
			// Whether we are setting (or getting)
			set = value !== undefined;

		// Try to normalize/fix the name
		name = notxml && jQuery.props[ name ] || name;

		// Only do all the following if this is a node (faster for style)
		if ( elem.tagName ) {

			// These attributes require special treatment
			var special = /href|src|style/.test( name );

			// Safari mis-reports the default selected property of a hidden option
			// Accessing the parent's selectedIndex property fixes it
			if ( name == "selected" && elem.parentNode )
				elem.parentNode.selectedIndex;

			// If applicable, access the attribute via the DOM 0 way
			if ( name in elem && notxml && !special ) {
				if ( set ){
					// We can't allow the type property to be changed (since it causes problems in IE)
					if ( name == "type" && elem.nodeName.match(/(button|input)/i) && elem.parentNode )
						throw "type property can't be changed";

					elem[ name ] = value;
				}

				// browsers index elements by id/name on forms, give priority to attributes.
				if( jQuery.nodeName( elem, "form" ) && elem.getAttributeNode(name) )
					return elem.getAttributeNode( name ).nodeValue;

				// elem.tabIndex doesn't always return the correct value when it hasn't been explicitly set
				// http://fluidproject.org/blog/2008/01/09/getting-setting-and-removing-tabindex-values-with-javascript/
				if ( name == "tabIndex" ) {
					var attributeNode = elem.getAttributeNode( "tabIndex" );
					return attributeNode && attributeNode.specified
						? attributeNode.value
						: elem.nodeName.match(/(button|input|object|select|textarea)/i)
							? 0
							: elem.nodeName.match(/^(a|area)$/i) && elem.href
								? 0
								: undefined;
				}

				return elem[ name ];
			}

			if ( !jQuery.support.style && notxml && name == "style" ) {
				if ( set )
					elem.style.cssText = "" + value;

				return elem.style.cssText;
			}

			if ( set )
				// convert the value to a string (all browsers do this but IE) see #1070
				elem.setAttribute( name, "" + value );

			var attr = !jQuery.support.hrefNormalized && notxml && special
					// Some attributes require a special call on IE
					? elem.getAttribute( name, 2 )
					: elem.getAttribute( name );

			// Non-existent attributes return null, we normalize to undefined
			return attr === null ? undefined : attr;
		}

		// elem is actually elem.style ... set the style
		// Using attr for specific style information is now deprecated. Use style insead.
		return jQuery.style(elem, name, value);
	}
});