代码检测textarea内填写的长度，未填写时提示需要重新填写，少于15字符时提示需要长于15字符，成功时显示所填写建议。
<script type="text/javascript">
//jQuery代码
function confirm()
{
if($("#advice").val().length == 0)
{
alert("We can't see your advice. Maybe you should fill the form first.");
$("#advice").focus();
return false;
}
else if($("#advice").val().length <= 15)
{
alert("Your advice should longer than 15 letters.");
$("#advice").focus();
return false;
}
else
{
alert("Thank you for your advice! You will get out reply in 24 hours for advice:\n"+$("#advice").val());
return true;
}
}
</script>
<form action="" method="post" onSubmit="return confirm();" >
<textarea id="advice" rows="20" cols="50"placeholder="Give us some advice?"></textarea>
<input type="submit"value="Thank you"/>
</form>
>关键点
1.必须要有onSubmit="return confirm();" return 这个词，不可缺少。
2.自行完整的网页结构。
以上所述就是本文的全部内容了，希望大家能够喜欢。