加载外部JavaScript文件 [英] Load External JavaScript File

问题描述

我正在尝试从javascript中加载外部javascript文件，但我似乎无法让它工作。我做错了什么？

I am trying to load an external javascript file from within javascript but I cannot seem to get it to work. Am I doing something wrong?

我工作的示例文件

function loadJs() {
var fileref=document.createElement('script')
fileref.setAttribute("type","text/javascript")
fileref.setAttribute("src", "https://ajax.googleapis.com/ajax/libs/jquery/1.7.1/jquery.min.js")
document.body.appendChild(fileref); }

推荐答案

也许您之前尝试访问jQuery API它满载。你可以像这样在loadJs函数中添加一个回调参数：

Perhaps you are trying to access the jQuery API before it is fully loaded. You can add a callback parameter to the loadJs function like this:

function loadJs(src, callback) {
    var s = document.createElement('script');
    document.getElementsByTagName('head')[0].appendChild(s);
    s.onload = function() {
        //callback if existent.
        if (typeof callback == "function") callback();
        callback = null;
    }
    s.onreadystatechange = function() {
        if (s.readyState == 4 || s.readyState == "complete") {
            if (typeof callback == "function") callback();
            callback = null; // Wipe callback, to prevent multiple calls.
        }
    }
    s.src = src;
}

loadJs('https://ajax.googleapis.com/ajax/libs/jquery/1.7.1/jquery.min.js', function() {
    $('body').append('<p>It works!</p>');
});

测试铬，FF，ie8。小提琴： http://jsfiddle.net/Umwbx/2/

Tested in chrome, FF, ie8. Fiddle: http://jsfiddle.net/Umwbx/2/

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