js 动态添加 外部js css 到head标签

function appendJQCDN() {
var head = document.head || document.getElementsByTagName('head')[0];
var script = document.createElement('script');
var style = document.createElement('style');
script.setAttribute("src", "https://cdn.bootcss.com/jquery/1.10.2/jquery.min.js");
style.innerHTML = '';
head.appendChild(script);
head.appendChild(style);

}

动态添加 js

function loadScript(url, callback) {
var script = document.createElement("script");
script.type = "text/javascript";
if (typeof (callback) != "undefined") {
if (script.readyState) {
script.onreadystatechange = function () {
if (script.readyState == "loaded" || script.readyState == "complete") {
script.onreadystatechange = null;
callback();
}
};
} else {
script.onload = function () {
callback();
};
}
};
script.src = url;
document.body.appendChild(script);
}

loadScript("https://cdn.bootcss.com/jquery/3.2.1/jquery.js", function() {

//加载,并执行回调函数

alert('动态引入jquery成功')

});