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.