<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.1//EN"
"http://www.w3.org/TR/xhtml11/DTD/xhtml11.dtd">
<html xmlns="http://www.w3.org/1999/xhtml" xml:lang="en">
<head>
<meta http-equiv="content-type" content="text/html; charset=utf-8" />
<title>processFile</title>
<link rel="stylesheet" type="text/css" href="css/processFile.css" />
</head>
<body> <script src="js/test.js" type="text/javascript" charset="utf-8" ></script> <!--存放源数据的js文件-->
<script type="text/javascript">
var transPart=document.getElementById("transmitBtn");
alert(transPart);
var srcContent=document.getElementById("srcFile");
alert(srcContent);
var properties=document.getElementById("properties"); </script>
<div id="content">
<div id="srcContent">
<div id="srcFile" class="border">
</div>
<div id="properties" class="border">
</div>
</div>
<div id="rstContent">
<input type="button" id="transmitBtn" name="transmitBtn" value="转换!"/>
</div>
</div>
</body>
</html>我尝试了以上代码,为什么三个alert得到的都是null呢?
"http://www.w3.org/TR/xhtml11/DTD/xhtml11.dtd">
<html xmlns="http://www.w3.org/1999/xhtml" xml:lang="en">
<head>
<meta http-equiv="content-type" content="text/html; charset=utf-8" />
<title>processFile</title>
<link rel="stylesheet" type="text/css" href="css/processFile.css" />
</head>
<body> <script src="js/test.js" type="text/javascript" charset="utf-8" ></script> <!--存放源数据的js文件-->
<script type="text/javascript">
var transPart=document.getElementById("transmitBtn");
alert(transPart);
var srcContent=document.getElementById("srcFile");
alert(srcContent);
var properties=document.getElementById("properties"); </script>
<div id="content">
<div id="srcContent">
<div id="srcFile" class="border">
</div>
<div id="properties" class="border">
</div>
</div>
<div id="rstContent">
<input type="button" id="transmitBtn" name="transmitBtn" value="转换!"/>
</div>
</div>
</body>
</html>我尝试了以上代码,为什么三个alert得到的都是null呢?
你把js放到</body>后面就可以了
window.onload = function(){
//放到这里
}或者把js放到页面的最后。
window.onload=function(){
var transPart=document.getElementById("transmitBtn");
alert(transPart);
var srcContent=document.getElementById("srcFile");
alert(srcContent);
var properties=document.getElementById("properties");
}
</script>
另一种做法是使用框架的ready事实,比onload快一点,不过差别基本上可以忽视。