vue动态加载js文件，加载完成后执行回调

方法定义：

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);
}

调用：

var that=this;//监听函数中的this不再指向组件本身，而是指向事件监听者,所以需要提前保存this指针
this.loadScript('xxx.js',function(){
    console.log('加载完成');
});