动态加载js、css 代码

一、原生js：

 /**
          * 加载js和css文件
          * @param         jsonData.path                前缀路径
          * @param         jsonData.url                需要加载的js路径或css路径
          * @param         jsonData.type                需要加载的类型 js或css
         */
          function loadWriteFiles(jsonData)
          {
              jsonData.path = jsonData.path != undefined ? jsonData.path : "";
              if(jsonData.type == "js")
              {
                 document.writeln("<script type='text/javascript' src='"+ jsonData.path + jsonData.url+"'></script>");
              }
              else if(jsonData.type == "css")
              {
                 document.writeln("<link rel='stylesheet' href='"+jsonData.path + jsonData.url+"' type='text/css' />");
              }
          }

          /**
           * 加载js或css到head中
           * @param         jsonData.path                前缀路径
           * @param         jsonData.url                需要加载的js路径或css路径
           * @param         jsonData.type                需要加载的类型 js或css
           */
          function loadFilesToHead(jsonData)
          {
              jsonData.path = jsonData.path != undefined ? jsonData.path : "";
              if(jsonData.type == "js")
              {
                  var _js = document.createElement("script");
                  _js.setAttribute("type", "text/javascript");
                  _js.setAttribute("src", jsonData.path + jsonData.url);
                  _js.onload = _js.onreadystatechange=function(){
                      if(!this.readyState||this.readyState=='loaded'||this.readyState=='complete'){
                          if("function" == typeof(jsonData["callback"]) && jsonData["callback"]){
                                 jsonData["callback"].call(this);
                          }
                      }
                      _js.onload=_js.onreadystatechange=null;
                  }
                  document.getElementsByTagName("head")[0].appendChild(_js);//追加到head标签内
              }
              else if(jsonData.type == "css")
              {
                  var _css = document.createElement("link");
                  _js.setAttribute("type", "text/css");
                  _css.setAttribute("rel", "stylesheet");
                  _css.setAttribute("href", jsonData.path + jsonData.url);
                  document.getElementsByTagName("head")[0].appendChild(_css);//追加到head标签内
              }
          }

二、jquery版本：

采用deferred对象返回结果

 var uiLoad = uiLoad || {};

 (function($, $document, uiLoad) {
     "use strict";

     var loaded = [],
     promise = false,
     deferred = $.Deferred();

     uiLoad.load = function (srcs) {
         srcs = $.isArray(srcs) ? srcs : srcs.split(/\s+/);
         if(!promise){
             promise = deferred.promise();
         }

       $.each(srcs, function(index, src) {
         promise = promise.then( function(){
             return src.indexOf('.css') >=0 ? loadCSS(src) : loadScript(src);
         } );
       });
       deferred.resolve();
       return promise;
     };

     var loadScript = function (src) {
         if(loaded[src]) return loaded[src].promise();

         var deferred = $.Deferred();
         var script = $document.createElement('script');
         script.src = src;
         script.onload = function (e) {
             deferred.resolve(e);
         };
         script.onerror = function (e) {
             deferred.reject(e);
         };
         $document.body.appendChild(script);
         loaded[src] = deferred;

         return deferred.promise();
     };

     var loadCSS = function (href) {
         if(loaded[href]) return loaded[href].promise();

         var deferred = $.Deferred();
         var style = $document.createElement('link');
         style.rel = 'stylesheet';
         style.type = 'text/css';
         style.href = href;
         style.onload = function (e) {
             deferred.resolve(e);
         };
         style.onerror = function (e) {
             deferred.reject(e);
         };
         $document.head.appendChild(style);
         loaded[href] = deferred;

         return deferred.promise();
     }

 })(jQuery, document, uiLoad);