ajax防止表單自動提交

重寫表單的checkForm方法，並用if和else解決非同步判斷的問題。

function checkForm(){
 1 var flag = false;    
 2 
 3 $.ajaxSetup({async : false});
 4 
 5 $.post(<?php echo "'".$SITE_PHP.'captchaAjax.php'."'";?>,'captcha='+document.getElementById("captcha").value,function(msg){if(!parseInt(msg)){layer.alert('驗證碼錯誤！',{time:1000});return flag;}else{
 6 
 7 $.post(<?php echo "'".$SITE_PHP.'loginNamePassAjax.php'."'";?>,'username='+document.getElementById("username").value+'&'+'password='+document.getElementById("password").value,function(msg){if(!parseInt(msg)){layer.alert('用戶名或密碼錯誤！',{time:1000});return flag;}else{
 8 
 9 flag = true;return flag;}});}});
10 
11 return flag;
}