function loadScript(url, callback) {
var script = document.createElement("script");
script.type = "text/javascript";
if (script.readyState) { //IE
script.onreadystatechange = function() {
if (script.readyState == "loaded" || script.readyState == "complete") {
script.onreadystatechange = null;
callback();
}
};
} else { //Others
script.onload = function() {
callback();
};
}
script.src = url;
document.getElementsByTagName("head")[0].appendChild(script);
}
转载于:https://www.cnblogs.com/arliang/archive/2011/10/08/js_load_script_and_trigger_callback.html