异步加载JS
<!DOCTYPE html><html lang="en"><head> ???<meta charset="UTF-8"> ???<title>异步加载js</title></head><body> ???<script> ???//异步加载JS函数 ???// 实现思想：动态创建script标签，插入到文档中，然后执行callback函数 ???//url为请求的JS文件的地址，callback为请求成功时的回调函数 ???function loadScript(url,callback){ ???????//动态创建script标签 ???????var script = document.createElement("script"); ???????script.type = "text/javascript"; ???????//判断外部的JS文件是否加载完成（此处需要解决浏览器的兼容问题） ???????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; ???????//执行脚本文件 ???????document.body.appendChild(script); ???} ???//调试程序 ???// loadScript("1.js",function(){ ???// ?test(); ???// }); ???</script> ???</body></html>异步加载JS
原文地址：https://www.cnblogs.com/thatme/p/10296546.html