$.post validate form field and blck submit is there is error

Question

I want to validate form field on submit and if ajax returns message to block the form submit. Here is the js code I have:

$('form.p_form').submit(function (){
var description = $.trim($('#f9').val());
var aa = $.post("checkdescription.php",{
     description: description
 },
 function(data, status){
    if(data !== ''){
    return data;
    }
 });

 if(aa){
 alert(aa);
 return false;
 }
});

but the code above always returns [object XMLHttpRequest] - How to read the mesage returned?

basicaly in checkdescription.php I have php code that validates the field and if there is error it puts in:

$return ='error message'; 

//file ends with:

echo json_encode($return);

how can I read the exact message received from response?

thank you in advance !

I also tried this:

    $('form.p_form').submit(function (){
var description = $.trim($('#f9').val());
var aa = $.post("checkdescription.php",{
     description: description
 },
 function(data, status){
    if(data !== ''){
    return false;
    }
 });

but it doesnt prevent form submit..

Have you tried printing the XMLHttpRequest to the console? If you inspect it, you might be able to find where your missing parameter is hiding in the object — jonny, Aug 11 '15 at 16:00
Possible duplicate of http://stackoverflow.com/questions/14220321/how-to-return-the-response-from-an-asynchronous-call — Rob M., Aug 11 '15 at 16:00

score 0 · Answer 1 · answered Aug 13 '15 at 02:54

It's required that you also set PHP header to application/json because, this output can be easily read by JQuery's ajax or $.post function, more a structured JSON output is also needed, here's how you should do it...

for PHP

<?php
$output = array('status'=>'true','message'=>'your error message');
//Setting up the output MIME type
header('Content-Type:application/json;');
//Providing Structured Output
echo json_encode($output);

this will be easily read by ajax...

For Javascript

$('form.p_form').submit(function (){
var description = $.trim($('#f9').val());
var aa = $.post("checkdescription.php",{
description: description
},
 function(data, status){
   return data['status'];
   }
});

$.post validate form field and blck submit is there is error

1 Answers1

for PHP

For Javascript