一般现代浏览器通过侦听事件获得脚本加载完成时的状态
var
script
=
document.createElement(
'
script
'
);
script.type = ' text/javascript ' ;
// Firefox, Chrome
script.onload = function (){
alert( ' script loaded! ' );
};
script.src = ' http://code.jquery.com/jquery-1.4.2.min.js ' ;
document.getElementsByTagName( ' head ' )[ 0 ].appendChild(script);
script.type = ' text/javascript ' ;
// Firefox, Chrome
script.onload = function (){
alert( ' script loaded! ' );
};
script.src = ' http://code.jquery.com/jquery-1.4.2.min.js ' ;
document.getElementsByTagName( ' head ' )[ 0 ].appendChild(script);
ie支持另外一种方式，会触发readystatechange事件
loading:开始下载
complete:所有数据已准备就绪
var script = document.createElement( ' script ' );
script.type = ' text/javascript ' ;
// IE
script.onreadystatechange = function (){
if (script.readyState == ' loaded ' || script.readyState == ' complete ' ){
script.onreadystatechange = null ;
alert( ' Script loaded ' );
}
}
script.src = ' http://code.jquery.com/jquery-1.4.2.min.js ' ;
document.getElementsByTagName( ' head ' )[ 0 ].appendChild(script);
兼容方法
/* *
* 载入脚本
* @param {String} url 载入的地址
* @param {Function} callback 载入后需执行的函数
*/
function loadScript(url, callback){
var script = document.createElement( ' script ' );
script.type = ' text/javascript ' ;
// IE
if (script.readyState){
script.onreadystatechange = function (){
if (script.readyState == ' loaded ' || script.readyState == ' complete ' ){
script.onreadystatechange = null ;
callback();
}
}
} else { // 非IE
script.onload = function (){
callback();
}
}
script.src = null ;
document.getElementsByTagName( ' head ' )[ 0 ].appendChild(script);
}
// example
loadScript( ' http://code.jquery.com/jquery-1.4.2.min.js ' , function (){
alert( ' File is loaded! ' );
})
XMLRequest脚本注入
var xhr = new XMLHttpRequest();
xhr.open( ' get ' , ' http://code.jquery.com/jquery-1.4.2.min.js ' , true );
xhr.onreadystatechange = function (){
if (xhr.readySate == 4 ){
if (xhr.status >= 200 && shr.status < 300 || xhr.status == 304 ){ // 200 有效响应; 304 从缓存读取
var script = document.createElement( ' script ' );
script.type = ' text/javascript ' ;
script.text = xhr.responseText;
document.body.appendChild(script);
}
}
};
xhr.send( null );
本文转自豪情博客园博客，原文链接：http://www.cnblogs.com/jikey/archive/2011/06/19/2084578.html，如需转载请自行联系原作者
