<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml">
<head>
<meta http-equiv="Content-Type" content="text/html; charset=utf-8" />
<title>无标题文档</title>
<script type="text/javascript" language="javascript">
function show(){
//获取文本框中的数字(方法一)
//var num = document.myform.number.value;
//document.write(num);
//获取文本框中的数字(方法二)
//var num = document.forms[0].number.value;
//document.write(num);
//获取文本框中的数字(方法三)
var num = document.getElementById("number").value;
//document.write(num);
for(var i=0;i<num;i++){
document.write("Hello World!");
document.write("<br>");
}
}
</script>
</head>
<body>
<form action="" method="post" name="myform">
<input type="text" id="number" name="number"/>
<input type="button" onclick="show()" value="显示" />
</form>
</body>
</html>
原文：http://www.cnblogs.com/danmao/p/3808609.html