使用onsubmit()验证表单并阻止非法提交(使用jQuery)

 1 <script type="text/javascript">
 2 //jQuery代码
 3 function confirm()
 4 {
 5 　　if($("#advice").val().length == 0)
 6 {
 7 　　alert("We can‘t see your advice. Maybe you should fill the form first.");
 8 　　$("#advice").focus();
 9 　　return false;
10 }
11 else if($("#advice").val().length <= 15)
12 {
13 　　alert("Your advice should longer than 15 letters.");
14 　　$("#advice").focus();
15 　　return false;
16 }
17 else
18 {
19 　　alert("Thank you for your advice! You will get out reply in 24 hours for advice:\n"+$("#advice").val());
20 　　return true;
21 }
22 
23 }
24 </script>
25 
26 <form action="" method="post" onSubmit="return confirm();" >
27 　　<textarea id="advice" rows="20" cols="50"placeholder="Give us some advice?"></textarea>
28　　 <input type="submit"value="Thank you"/>
29 </form>