JS添加验证页面中script标签中是否存在jquery文件

 window.onload = function()
 {
 var al = document.getElementsByTagName("script");
 var new_element=document.createElement("script");
 var joine = []
 for(var i = 0; i<al.length; i++)
 {
     joine.push(al[i].getAttribute("src"));
 }
 var ajoine = joine.join(",");
 console.log(ajoine);
 if(IndexDemo(ajoine,'jquery.min.js')>0)
     {
         console.log('1');
         //alert(1);
     }else{
         console.log('2');
         var new_element=document.createElement("script");
         new_element.setAttribute("type","text/javascript");
         new_element.setAttribute("src","/static/js/jquery-1.5.1/jquery.min.js");// 在这里引入了a.js
         document.body.appendChild(new_element);
         //alert(2);
     }
 }

 function IndexDemo(str1,str2){
    var list = str1
    var s = list.indexOf(str2);
    return(s);
 }

IndexDemo() 方法查询字符.

var ajoine = joine.join(",");  方法 数组转字符串.

可修改参数去实现自己的判断效果.