<script LANGUAGE="javascript">
<!--
function checkNum(str){return !/\d{6}/.test(str)}
function check()
{
if (document.form.tell.value==""){
  alert("請輸入電話號碼！");

  document.form.tell.focus();
  return false;
}
else{
  var Letters = "0123456789()+-";
  for (i=0; i< document.form.tell.value.length; i++){
     var CheckChar = document.form.tell.value.charAt(i);
     if (Letters.indexOf(CheckChar) == -1){
       alert("電話號碼格式不正確！");
       document.form.tell.focus();
       return false;
      }
    }
  }
}
//-->
</script>

<form method="POST" name=form action="" onSubmit="return check();">
<p align="center">
   请输入电话号码：<input type="text" name="tell" size="20">
<input type="submit" value="提交" name="B1"></p>
</form>