php：如何使用jquery ajax验证文本框

Question

I have a textbox, i would like to validate it using jquery-ajax once user focusout from that textbox.

Validation include:

• Server side, value goes to the php page and i have to validate it

• if validation success,show alert("succes"); else if error alert("failed");

I have doubt how jquery ajax will show alert("failure"); Till now , i have only done for success.

I know only the below mention code,furthure what should i do to solve my problem? please help

<script type="text/javascript">
    $(function()
    {
        $('input[id^="datepicker"]').on('focusout',function()
        { 
             $.ajax({
                url: "ajax_frmdate_validation.php?txtval="+$(this).val(),
                success: function(data){
                    alert('Successfully  ...');
                }
            });

        });
    });
</script>

--------------
--------------
<input class="plain" name="frmdate"   value="" size="25" id="datepicker" /> 

And my server side php code is:

$txtval =$_REQUEST['txtval'];
$fromTimestamp = strtotime( $txtval); 
//---------My Logic Code Goes Here -----------------------------
$sid=$_SESSION['id'];
$result12=mysql_query("SELECT * FROM budget where creater_id = '$sid'");
$num_rows = mysql_num_rows($result12);

if($num_rows>0)//check if empty or not
{
    while($test12 = mysql_fetch_array($result12)) {
        $from_date = strtotime($test12['from_date']);//getting all the FROM-Dates_column
        $to_date = strtotime($test12['to_date']);//getting all the TO-Dates_column

        if(isset($to_date) && isset($from_date)) {
            if((($fromTimestamp >= $from_date) && ($fromTimestamp <= $to_date)) || (($toTimestamp >= $from_date) && ($toTimestamp <= $to_date))) {
                $val = 'Y'; //return Y in meet this condition
            }
            else {
                $val = 'N'; // return N if meet this condition
            }
        }
        //---------------------Result of my logic code---------------------------------
        if($val == 'Y') //Returns TRUE
        {
            //VALIDATION FAILS - Returns Validation Error
            break;
        }
        else  if($val == 'N') {
            //VALIDATION TRUE - Returns Validation Error
        }
    }
}

Answer 1

You can do this way:

$txtval = mysql_real_escape_string($_REQUEST['txtval']);
$fromTimestamp = strtotime( $txtval); 
 //---------My Logic Code Goes Here -----------------------------
 $sid=$_SESSION['id'];
 $result12=mysql_query("SELECT * FROM budget where creater_id = '$sid'");
 $num_rows = mysql_num_rows($result12);

 if($num_rows>0)//check if empty or not
 {
    while($test12 = mysql_fetch_array($result12)) {
    $from_date = strtotime($test12['from_date']);//getting all the FROM-Dates_column
    $to_date = strtotime($test12['to_date']);//getting all the TO-Dates_column

    if(isset($to_date) && isset($from_date)) {
         if((($fromTimestamp >= $from_date) && ($fromTimestamp <= $to_date)) || (($toTimestamp >= $from_date) && ($toTimestamp <= $to_date))) {
             $val = 'Y'; //return Y in meet this condition
         }
         else {
            $val = 'N'; // return N if meet this condition
         }
     }
     //---------------------Result of my logic code---------------------------------
     if($val == 'Y') //Returns TRUE
     {
        echo "failed";
        exit();
     }
     else  if($val == 'N') 
     {
        echo "success";
        exit();
     }

Now in your ajax call:

<script type="text/javascript">
    $(function()
    {
       $('input[id^="datepicker"]').on('focusout',function()
       { 
         $.ajax({
            url: "ajax_frmdate_validation.php?txtval="+$(this).val(),
            success: function(data){
               if (data == 'success') {
                    alert("Successfully validated"); 
               } else {
                    alert("Failed");
                    return false;
               }
            }
        });

      });
   });
</script>

Rather than alerting, a better way will be to show the error message below the textbox by appending the message if it is failed.

Also do proper escaping before you do the checking using mysql_real_escape_string

UPDATE :

You need to call the ajax whenever the date changes in the input text field, so instead of focusout you can use onSelect from datepicker. So when a new date is selected an ajax call will be initiated.

So instead of calling the earlier ajax on focusout you can call on onSelect of datepicker

$(function(){
    $('#datepicker').datepicker({
        onSelect:function(date,instance){
           $.ajax({
              url: "ajax_frmdate_validation.php?txtval="+date,
              success: function(data){
                 if (data == 'success') {
                    alert("Successfully validated"); 
                 } else {
                    alert("Failed");
                    return false;
                 }
              }
           });
        }
    });
}); 

NEW UPDATE

Try with this :

 <script type="text/javascript">
     $(document).ready(function() { 
       $("#datepicker").datepicker({ 
          dateFormat: "yy-mm-dd" ,
          onSelect:function(date,instance){
                          $.ajax({
                            url: "ajax_frmdate_validation.php?txtval="+date,
                            success: function(data){
                            if (data == 'success') {
                                 alert("Successfully validated"); 
                            } else {
                                 alert("Failed");
                                  return false;
                            }
                     }
                 });
            }
     }); 
  }); 
 </script>