用script标签异步加载js
1 function loadScript(url, callback){ 2 var script = document.createElement ("script") 3 script.type = "text/javascript"; 4 if (script.readyState){ //IE 5 script.onreadystatechange = function(){ 6 if (script.readyState == "loaded" || script.readyState == "complete"){ 7 script.onreadystatechange = null; 8 callback(); 9 } 10 }; 11 } else { //Others 12 script.onload = function(){ 13 callback(); 14 }; 15 } 16 script.src = url; 17 document.getElementsByTagName_r("head")[0].appendChild(script); 18 }