jQuery.className.has的定义可以改进成：
has: function( t, c ) {
t = t.className || t;
t = " " + t + " ";
c = " " + c + " ";
return t.indexOf(c)>-1;
}

className: {
// internal only, use addClass("class")
add: function( elem, c ){
jQuery.each( c.split(/\s+/), function(i, cur){
if ( !jQuery.className.has( elem.className, cur ) )
elem.className += ( elem.className ? " " : "" ) + cur;
});
},
// internal only, use removeClass("class")
remove: function( elem, c ){
elem.className = c ?
jQuery.grep( elem.className.split(/\s+/), function(cur){
return !jQuery.className.has( c, cur );
}).join(" ") : "";
},
// internal only, use is(".class")
has: function( t, c ) {
t = t.className || t;
// escape regex characters
c = c.replace(/([\.\\\+\*\?\[\^\]\$\(\)\{\}\=\!\<\>\|\:])/g, "\\$1");
return t && new RegExp("(^|\\s)" + c + "(\\s|$)").test( t );
}
},
swap: function(e,o,f) {
for ( var i in o ) {
e.style["old"+i] = e.style[i];
e.style[i] = o[i];
}
f.apply( e, [] );
for ( var i in o )
e.style[i] = e.style["old"+i];
},
css: function(e,p) {
if ( p == "height" || p == "width" ) {
var old = {}, oHeight, oWidth, d = ["Top","Bottom","Right","Left"];
jQuery.each( d, function(){
old["padding" + this] = 0;
old["border" + this + "Width"] = 0;
});
jQuery.swap( e, old, function() {
if (jQuery.css(e,"display") != "none") {
oHeight = e.offsetHeight;
oWidth = e.offsetWidth;
} else {
e = jQuery(e.cloneNode(true))
.find(":radio").removeAttr("checked").end()
.css({
visibility: "hidden", position: "absolute", display: "block", right: "0", left: "0"
}).appendTo(e.parentNode)[0];
var parPos = jQuery.css(e.parentNode,"position");
if ( parPos == "" || parPos == "static" )
e.parentNode.style.position = "relative";
oHeight = e.clientHeight;
oWidth = e.clientWidth;
if ( parPos == "" || parPos == "static" )
e.parentNode.style.position = "static";
e.parentNode.removeChild(e);
}
});
return p == "height" ? oHeight : oWidth;
}
return jQuery.curCSS( e, p );
},
curCSS: function(elem, prop, force) {
var ret;
if (prop == "opacity" && jQuery.browser.msie)
return jQuery.attr(elem.style, "opacity");
if (prop == "float" || prop == "cssFloat")
prop = jQuery.browser.msie ? "styleFloat" : "cssFloat";
if (!force && elem.style[prop])
ret = elem.style[prop];
else if (document.defaultView && document.defaultView.getComputedStyle) {
if (prop == "cssFloat" || prop == "styleFloat")
prop = "float";
prop = prop.replace(/([A-Z])/g,"-$1").toLowerCase();
var cur = document.defaultView.getComputedStyle(elem, null);
if ( cur )
ret = cur.getPropertyValue(prop);
else if ( prop == "display" )
ret = "none";
else
jQuery.swap(elem, { display: "block" }, function() {
var c = document.defaultView.getComputedStyle(this, "");
ret = c && c.getPropertyValue(prop) || "";
});
} else if (elem.currentStyle) {
var newProp = prop.replace(/\-(\w)/g,function(m,c){return c.toUpperCase();});
ret = elem.currentStyle[prop] || elem.currentStyle[newProp];
}
return ret;
},