js弹窗出错。高手帮改一下。解决思路

<?php
$qq=$_POST['qq'];
if(!$qq==""){
    if( strlen( $qq ) > 12 || strlen( $qq ) < 5 ||[b] !is_numeric( $qq ) || $qq < 0 [/b]){
        echo"<script language='javascript'> alert('对不起,你输入的QQ号码无效.请重新输入.');history.back();</script>";
        exit();
    }
?>

<form  name="form1" method="post" action="">
QQ号码吉凶查询:  <input type="text" name="qq" onkeyup="value=value.replace(/[^\d]/g,'')">
<input type="hidden" name ="postclick" value="true" />
<input type="submit" name="Submity" value="查询">
<input type="reset" name="Submit2" value="重置">
</form>