<script language=Javascript> //自己动手为string添加Trim
function String.prototype.Trim() {return this.replace(/(^\s*)|(\s*$)/g,"");}
function String.prototype.Ltrim(){return this.replace(/(^\s*)/g, "");}
function String.prototype.Rtrim(){return this.replace(/(\s*$)/g, "");}
var str = " fason ";
alert(str.Trim());
</script>
function String.prototype.Trim() {return this.replace(/(^\s*)|(\s*$)/g,"");}
function String.prototype.Ltrim(){return this.replace(/(^\s*)/g, "");}
function String.prototype.Rtrim(){return this.replace(/(\s*$)/g, "");}
var str = " fason ";
alert(str.Trim());
</script>
javascript本没有trim（）函数，自己动手打造为string添加Trim
<script language=Javascript> //自己动手为string添加Trim
function String.prototype.Trim() {return this.replace(/(^\s*)|(\s*$)/g,"");}
function String.prototype.Ltrim(){return this.replace(/(^\s*)/g, "");}
function String.prototype.Rtrim(){return this.replace(/(\s*$)/g, "");}
var str = " meizz ";
alert(str.Trim());
alert(str.Ltrim());
alert(str.Rtrim());
</script>
<input type="text" name="text1" onKeypress="if(event.keyCode<48||event.keyCode>57) event.returnValue = false;">
<html>
<head>
<title>无标题文档</title>
<meta http-equiv="Content-Type" content="text/html; charset=gb2312">
<script language=javascript>
function checktext(){
if(document.form1.text1.value!="开发"){
alert("输入有误，请从新输入！");
document.form1.text1.focus();
return false;
}else{
return true;
}
}
</script>
</head><body bgcolor="#FFFFFF" text="#000000">
通常验证文本框中的值可以通过表单的onSubmit事件
<form name=form1 onSubmit="return checktext();">
<input type="text" name="text1">
<input type="submit" name="Submit" value="提交">
</form></body>
</html>
alert(trim(form1.str1.value));
<script>