按需加载js文件的形式（转）

//需要按需加载的内部文件列表映射
mis.classFiles = {
  'AjaxEvent': 'includes/ajax.lib.js',
  'AjaxRequest': 'includes/request.lib.js',
  'colorFade': 'includes/effects.lib.js'
}
//标记已经include的内部文件
mis.includedFiles = {};
//对内的文件加载
mis.include = function(classname,callback){
  if(mis.includedFiles[classname]){
    callback && callback();
    return true;
  }else if(mis.classFiles[classname]){
    return mis.loadJavaScript(mis.classFiles[classname],callback);
  }else{
    return false;
  }
}
//标记已经load的内部和外部文件
mis.loadedJavaScript = {}
//无限制的加载file文件
mis.loadJavaScript = function(file,callback){
  callback = callback || function(){};
  if(mis.loadedJavaScript[file]){
    callback(true);
    return true;
  }else{
    var head = document.getElementsByTagName("head")[0];
    var script = head.appendChild(document.createElement("script"));
    script.onload = script.onreadystatechange = function(){
      if((!/*@cc_on!@*/0) || (/loaded|complete/).test(script.readyState)){
        script.onreadystatechange = null;
        mis.loadedJavaScript[file] = true;
        callback(true);
      }
    }
    script.src = file;
    return true;
  }
}

原文：http://www.ilovejs.net/archives/1545

转载于:https://www.cnblogs.com/sking7/archive/2011/10/12/2208707.html