试试
<input type="text" name="o_phone" size="12" onchange="if(/\D/.test(o_phone.value)){alert('只能输入数字');this.value='';this.focus();}">
<input type="text" name="o_phone" size="12" onchange="if(/\D/.test(o_phone.value)){alert('只能输入数字');this.value='';this.focus();}">
function check(){
var price = form1.unit_price.value;
if(!(price.match(/\D/)==null))
{
alert("不全是数字!");
document.form1.unit_price.focus();
return false;
}
}
</script>
<form name=form1>
<input type="text" name="unit_price" size="12" onblur=check()>
<input type="text" name="o_phone" size="12">
</form>
<head>
<script language="javascript">
function check_num()
{
value1=document.form1.text1.value;
if(isNaN(value1)){alert('输入字符非法');}
}
</script>
</head>
<body>
<form name=form1 method='post'onsubmit="check_num()" >
<input type=text name=text1>
</form>
</body>
</html>