动态加载脚本

 1 function loadScript(url, callback) {

 2     var script = document.createElement("script");

 3     script.type = "text/javascript";

 4 

 5     if (script.readyState) { //IE

 6         script.onreadystatechange = function() {

 7             if (script.readyState == "loaded" || script.readyState == "complete") {

 8                 script.onreadystatechange = null;

 9                 callback();

10             }

11         };

12     } else {

13         script.onload = function() { //其他浏览器

14             callback();

15         };

16     }

17     script.src = url;

18     document.getElementsByTagName("head")[0].appendChild(script);

19 }

 

用法如下：

 1 loadScript("file1.js", function() {

 2     console.log("File is loaded!");

 3 });

 4 loadScript("file1.js", function() {

 5     loadScript("file2.js", function() {

 6         loadScript("file3.js", function() {

 7             console.log("All files are loaded!");

 8         });

 9     });

10 });