document.ready 与 onload 的区别

时间 2019-11-08

标签 document.ready document ready onload 区别繁體版

原文原文链接

摘要

document.ready 是指文档加载好, dom 加载好，仅包含在它以前的 script 、css 标签，但不包含 img 标签是否加载完成，由于页面是按顺序执行的。javascript

onload 是指页面彻底加载好，包括全部节点，甚至 img 标签css

固然咱们编码通常都是把基础库放在head 头部，保证最早加载，业务代码放在最后，避免出现库未加载完成的状况。html

固然如今前端工程通常使用 webpack 等打包技术，在编译打包过程当中就彻底实现了依赖项前置的功能。前端

测试

<!DOCTYPE html>
<html>
<head>
    <title></title>
</head>

<body onload="onload()">
    <img src="http://upload.chinaz.com/upimg/allimg/110630/0901070.jpg" />
    <script type="text/javascript" src="http://libs.cdnjs.net/jquery/3.2.1/jquery.min.js"></script>
    <script type="text/javascript">
        $(document).ready(function() {
            console.log('document ready');
        });
    </script>
    <script type="text/javascript">
        console.log('haha');
    </script>
</body>

<script type="text/javascript">
function onload() {
    console.log('onload');
}
</script>
</html>
// 打印   
//haha
//document ready     
//onload

<!DOCTYPE html>
<html>
<head>
    <title></title>
</head>

<body onload="onload()">
    <img src="http://upload.chinaz.com/upimg/allimg/110630/0901070.jpg" />
    <script type="text/javascript">
        $(document).ready(function() {
            console.log('document ready');
        });
    </script>
    <script type="text/javascript">
        console.log('haha');
    </script>
    <script type="text/javascript" src="http://libs.cdnjs.net/jquery/3.2.1/jquery.min.js"></script>
</body>

<script type="text/javascript">
function onload() {
    console.log('onload');
}
</script>
</html>
//打印  
//$ undefined    
//haha   
//onload

<!DOCTYPE html>
<html>
<head>
    <title></title>
</head>

<body onload="onload()">
    <img src="http://upload.chinaz.com/upimg/allimg/110630/0901070.jpg" />

    <script type="text/javascript">
        console.log('haha');
    </script>
    <script type="text/javascript">
        $(document).ready(function() {
            console.log('document ready');
        });
    </script>
    <script type="text/javascript" src="http://libs.cdnjs.net/jquery/3.2.1/jquery.min.js"></script>

</body>

<script type="text/javascript">
function onload() {
    console.log('onload');
}
</script>
</html>
//打印  
//haha   
//$ undefined    
//onload