js代码动态加载js文件，并在加载成功后执行回调函数

用Jquery就是:

loadScript("file1.js", function(){
alert("File is loaded!");

});

用原生代码:

function loadScript(src, callback) {
    var script = document.createElement('script'),
        head = document.getElementsByTagName('head')[0];
    script.type = 'text/javascript';
    script.charset = 'UTF-8';
    script.src = src;
    if (script.addEventListener) {
        script.addEventListener('load', function () {
            callback();
        }, false);
    } else if (script.attachEvent) {
        script.attachEvent('onreadystatechange', function () {
            var target = window.event.srcElement;
            if (target.readyState == 'loaded') {
                callback();
            }
        });
    }
    head.appendChild(script);

}

原帖:https://www.cnblogs.com/webarn/p/6814402.html