代碼檢測textarea內填寫的長度，未填寫時提示需要重新填寫，少於15字符時提示需要長於15字符，成功時顯示所填寫建議。
<script type="text/javascript">
//jQuery代碼
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>
>關鍵點
1.必須要有onSubmit="return confirm();" return 這個詞，不可缺少。
2.自行完整的網頁結構。
以上所述就是本文的全部內容了，希望大家能夠喜歡。