超过字数即使提醒

<script language=javascript>

function gbcount(message,total,used,remain)

{

var max;

max= total.value;

if(message.value.length > max){

message.value = message.value.substring(0,max);

used.value = max;

remain.value = 0;

alert('留言不能超过规定的字数!');

}

else{

used.value = message.value.length;

remain.value = max - used.value;

}

}

</script>



<form name='myform' >

<textarea name='GuestContent' cols='59' rows='6' onkeydown=gbcount(this.form.GuestContent,this.form.total,this.form.used,this.form.remain); onkeyup=gbcount(this.form.GuestContent,this.form.total,this.form.used,this.form.remain);></text_area>

最多字数：<INPUT disabled maxLength=4 name=total size=3 value=20>

已用字数：<INPUT disabled maxLength=4 name=used size=3 value=0>

剩余字数：<INPUT disabled maxLength=4 name=remain size=3>

</form>