请问页面里的javascript为什么不执行，没有弹出alaert？？<html>
<head>
<title>JavaScript Loan Calculator</title><script type="text/JavaScript">var aaaa =document.getElementById('indexsrh1').innerText;
alert(aaaa);</script>
</head><body>
<div id="indexsrh1">1</div>
<div id="indexsrh2">2</div>
</body>
</html>
<head>
<title>JavaScript Loan Calculator</title><script type="text/JavaScript">var aaaa =document.getElementById('indexsrh1').innerText;
alert(aaaa);</script>
</head><body>
<div id="indexsrh1">1</div>
<div id="indexsrh2">2</div>
</body>
</html>
<script type="text/JavaScript">
window.onload = function(){
var aaaa =document.getElementById('indexsrh1').innerText;
alert(aaaa);
};
</script>