一些常用而且必须记住的公共JS函数

 

(function(doc,undefined){
 var win = this;
 win.Sys = function (ua){
  var b = {
   ie: /msie/.test(ua) && !/opera/.test(ua),
   opera: /opera/.test(ua),
   safari: /webkit/.test(ua) && !/chrome/.test(ua),
   firefox: /firefox/.test(ua),
   chrome: /chrome/.test(ua)
  },vMark = "";
  for (var i in b) {
   if (b[i]) { vMark = "safari" == i ? "version" : i; break; }
  }
  b.version = vMark && RegExp("(?:" + vMark + ")[\\/: ]([\\d.]+)").test(ua) ? RegExp.$1 : "0";
  b.ie6 = b.ie && parseInt(b.version, 10) == 6;
  b.ie7 = b.ie && parseInt(b.version, 10) == 7;
  b.ie8 = b.ie && parseInt(b.version, 10) == 8; 
  return b;
 }(win.navigator.userAgent.toLowerCase());
 
 win.Sys.ie6&&doc.execCommand("BackgroundImageCache", false, true);
 
 win.$$ = function(id){
  return typeof id === 'string'
   ? doc.getElementById(id)
   : id;
 };
 win.$q = function(name,parent){
  return parent.getElementsByTagName(name);
 }
 win.$c = function(name,parent){
  var elem = typeof name ==='object'? name : doc.createElement(name);
  parent&&parent.appendChild(elem);
  return elem;  
 };
 
 win.addListener = function(element,e,fn){
  !element.events&&(element.events = {});
  element.events[e]&&(element.events[e][addListener.guid++]=fn)||(element.events[e] = {'0':fn});
  element.addEventListener?element.addEventListener(e,fn,false):element.attachEvent("on" + e,fn);
 };
 win.addListener.guid = 1;
 win.removeListener = function(element,e,fn){
  var handlers = element.events[e],type;
  if(fn){
   for(type in handlers)
    if(handlers[type]===fn){
     element.removeEventListener?element.removeEventListener(e,fn,false):element.detachEvent("on" + e,fn);
     delete handlers[type];
    }
  }else{
   for(type in handlers){
    element.removeEventListener?element.removeEventListener(e,handlers[type],false):element.detachEvent("on" + e,handlers[type]);
    delete handlers[type];
   }
  }      
 };
 win.fireEvent = function(element,eventName){
  if(element[eventName]){
   element[eventName]();
  }else if(element.fireEvent){
   element.fireEvent('on'+eventName);
  }else if(doc.createEvent){
   var evt = doc.createEvent("MouseEvents");
   evt.initEvent(eventName, true, true);
   element.dispatchEvent(evt);
  } 
 };
 win.setStyle = function(elems, style, value){
  if( !elems.length ) elems = [elems];
  if( typeof style == "string"){      
   style = value === undefined?{cssText:style}:(function(o){
    return (o[style] = value,o);          
   })({});
  };
  each(elems,function(i,elem,style){
   var value,name,ie=Sys.ie ;
   for(name in style){
    value = style[name];
    if (name === "opacity" && ie) {
     elem.style.filter = (elem.currentStyle.filter || "").replace( /alpha\([^)]*\)/, "" ) + "alpha(opacity=" + value * 100 + ")";
    }else if(name === "float"){
     elem.style[ ie ? "styleFloat" : "cssFloat" ] = value;
    }else{
     name = name.replace(/-([a-z])/ig, function(all, letter){
      return letter.toUpperCase();
     });
     elem.style[name] = value;
    }
   }
  },style);
 };
 win.setAttr = function(dom,attr){
  if(typeof attr !== 'object')
   return;
  for(var name in attr)
   dom.setAttribute(name,attr[name]);
 }
 
 var slice = Array.prototype.slice;
 win.bind = function(object, fun) {
  var args = slice.call(arguments).slice(2);
  return function() {
    return fun.apply(object, args);
  };
 };
 
 win.bindAsEventListener = function(object, fun,args) {
  var args = slice.call(arguments).slice(2);
  return function(event) {
   return fun.apply(object, [event || win.event].concat(args));
  }
 };

 win.extend = function(){
  var target = arguments[0] || {}, i = 1, length = arguments.length, deep = true, options;
  if ( typeof target === "boolean" ) {
   deep = target;
   target = arguments[1] || {};
   i = 2;
  }
  if ( typeof target !== "object" && Object.prototype.toString.call(target)!="[object Function]")
   target = {};
  for(;i<length;i++){
   if ( (options = arguments[ i ]) != null )
    for(var name in options){
     var src = target[ name ], copy = options[ name ];
     if ( target === copy )
      continue;
     if ( deep && copy && typeof copy === "object" && !copy.nodeType ){
      target[ name ] = arguments.callee( deep, src || ( copy.length != null ? [ ] : { } ), copy );
     }  
     else if(copy !== undefined)
      target[ name ] = copy;                      
    }
  }
  return target;          
 };
 
 win.Class = function(properties){
  var _class = function(){
   return (arguments[0] !== null && this.initialize && typeof(this.initialize) == 'function')
    ? this.initialize.apply(this, arguments)
    : this;
  };
  _class.prototype = properties;
  return _class;
 }; 

 win.each =  function ( object, callback, args ) { 
  var name, i = 0, length = object.length; 
  if ( args ) {
   args = Array.prototype.slice.call(arguments).slice(2);
   if ( length === undefined ) { 
    for ( name in object ) 
     if ( callback.apply( object[ name ],[name,object[ name ]].concat(args) ) === false ) 
      break; 
   } else
    for ( ; i < length; i++) 
     if ( callback.apply( object[ i ],[i,object[ i ]].concat(args)) === false )   //
      break; 
  } else {    
   if ( length === undefined ) { 
    for ( name in object ) 
     if ( callback.call( object[ name ], name, object[ name ] ) === false ) 
      break; 
   } else
    for ( var value = object[0]; 
     i < length && callback.call( value, i, value ) !== false; value = object[++i] ){} 
  } 
  return object; 
 }; 
 win.currentStyle = function(element){
  return element.currentStyle || doc.defaultView.getComputedStyle(element, null);
 };
 win.objPos = function(elem){
  var left = 0, top = 0, right = 0, bottom = 0,doc = elem ? elem.ownerDocument : doc;
  if ( !elem.getBoundingClientRect || win.Sys.ie8 ) {
   var n = elem;
   while (n) { left += n.offsetLeft, top += n.offsetTop; n = n.offsetParent; };
   right = left + elem.offsetWidth; bottom = top + elem.offsetHeight;
  } else {
   var rect = elem.getBoundingClientRect();
   left = right = doc.documentElement.scrollLeft || doc.body.scrollLeft;
   top = bottom = doc.documentElement.scrollLeft || doc.body.scrollLeft;
   left += rect.left; right += rect.right;
   top += rect.top; bottom += rect.bottom;
  }
  return { "left": left, "top": top, "right": right, "bottom": bottom };      
 };
 win.contains = function(k,j){
  return document.compareDocumentPosition
   ? k.compareDocumentPosition(j)&16
   : k!==j&&k.contains(j);
 };
 win.hasClass = function(element, className){
  return element.className.match(new RegExp('(\\s|^)'+className+'(\\s|$)'));
 };
 win.addClass = function(element, className){
  if(!win.hasClass(element, className))
   element.className.replace(/\s/g,'')===''
    ? element.className = className
    : element.className+= " "+className;
 };
 win.removeClass = function(element, className){
  win.hasClass(element, className)&&(element.className = element.className.replace(new RegExp('(\\s*|^)'+className+'(\\s*|$)'),' '));
 }
})(document);