jQuery Post and Get Form data

Question

When a form is submitted, I can get its field values with $_POST. However, I am trying to use a basic jQuery (without any plugin) to check if any field was blank, I want to post the form content only if theres no any blank field.

I am trying following code, and I got the success with jQuery, but the only problem is that I am unable to post the form after checking with jQuery. It does not get to the $_POST after the jQuery.

Also, how can I get the server response back in the jQuery (to check if there was any server error or not). Here's what I'm trying:

HTML:

<form action="" id="basicform" method="post">
    <p><label>Name</label><input type="text" name="name" /></p>
    <p><label>Email</label><input type="text" name="email" /></p>  

    <input type="submit" name="submit" value="Submit"/>
</form>

jQuery:

jQuery('form#basicform').submit(function() {
    //code
    var hasError = false;

    if(!hasError) {
            var formInput = jQuery(this).serialize();
            jQuery.post(jQuery(this).attr('action'),formInput, function(data){

            //this does not post data
            jQuery('form#basicform').slideUp("fast", function() {
                    //how to check if there was no server error.
                });
            });
        }               
    return false;


});

PHP:

if(isset($_POST['submit'])){
    $name = trim($_POST['name'];
    $email = trim($_POST['email'];  

    //no any error
    return true;
}

Answer 1

To be very specific to the question:

How can I get the server response back in the jQuery (to check if there was any server error or not). Here's what I'm trying:

Sound like you're talking about Server-Side validation via jQuery-Ajax.

Well, then you need:

• Send JavaScript values of the variables to PHP
• Check if there any error occurred
• Send result back to JavaScript

So you're saying,

However, I am trying to use a basic jQuery (without any plugin) to check if any field was blank, I want to post the form content only if there's no any blank field.

JavaScript/jQuery code:

Take a look at this example:

<script>
$(function()) {
    $("#submit").click(function() {
        $.post('your_php_script.php', {
             //JS Var   //These are is going to be pushed into $_POST
             "name"   : $("#your_name_field").val(),
             "email"  : $("#your_email_f").val()
        }, function(respond) {
           try {
               //If this falls, then respond isn't JSON 
               var result = JSON.parse(respond);

               if ( result.success ) { alert('No errors. OK')  }
           } catch(e) {
               //So we got simple plain text (or even HTML) from server
               //This will be your error "message" 
               $("#some_div").html(respond);
           }
       });
   });
}
</script>

Well, not it's time to look at php one:

<?php

/**
 * Since you're talking about error handling
 * we would keep error messages in some array
 */

$errors = array();

function add_error($msg){
  //@another readers 
  //s, please don't tell me that "global" keyword makes code hard to maintain
  global $errors;
  array_push($errors, $msg);
}

/**
 * Show errors if we have any
 * 
 */
function show_errs(){
   global $errors;
   if ( !empty($errors) ){

     foreach($errors as $error){
        print "<p><li>{$error}</li></p>";
     }
     //indicate that we do have some errors:
     return false;
   }
  //indicate somehow that we don't have errors
  return true;
}



function validate_name($name){
  if ( empty($name) ){
     add_error('Name is empty');   
  }

  //And so on... you can also check the length, regex and so on
  return true;
}


//Now we are going to send back to JavaScript via JSON 

if ( show_errs() ){
   //means no error occured

   $respond = array();
   $respond['success'] = true;
   //Now it's going to evaluate as valid JSON object in javaScript
   die( json_encode($respond) );

} //otherwise some errors will be displayed (as html)

Answer 2

There are two ways of doing that

Way 1:

As per your implementation, you are using input[type="submit"] Its default behavior is to submit the form. So if you want to do your validation prior to form submission, you must preventDefault() its behaviour

    jQuery('form#basicform').submit(function(e) {
        //code
e.preventDefault();
        var hasError = false;

        if(!hasError) {
                var formInput = jQuery(this).serialize();
                jQuery.post(jQuery(this).attr('action'),formInput, function(data){

                //this does not post data
                jQuery('form#basicform').slideUp("fast", function() {
                        //how to check if there was no server error.
                    });
                });
            }        
$(this).submit();       
        return false;


    });

Way 2:

Or simply replace your submit button with simple button, and submit your form manually. With $("yourFormSelector").submit();

Change your submit button to simple button

i.e Change

<input type="submit" name="submit" value="Submit"/>

To

<input id="frmSubmit" type="button" name="submit" value="Submit"/>

And your jQuery code will be

jQuery('input#frmSubmit').on('click',function(e) {
        //code
        var hasError = false;

        if(!hasError) {
                var formInput = jQuery(this).serialize();
                jQuery.post(jQuery(this).attr('action'),formInput, function(data){

                //this does not post data
                jQuery('form#basicform').slideUp("fast", function() {
                        //how to check if there was no server error.
                    });
                });
            }        
$("form#basicform").submit();       
        return false;


    });

To get the response from the server, you have to echo your response.

Suppose, if all the variables are set, then echo 1; else echo 0.

   if(isset($_POST['submit'])){
        $name = trim($_POST['name'];
        $email = trim($_POST['email'];  
        echo 1;
    } else {
        echo 0;
    }

And in your success callback function of $.post() handle it like

jQuery.post(jQuery(this).attr('action'),formInput, function(data){
                //this does not post data
                jQuery('form#basicform').slideUp("fast",{err:data}, function(e) {
                        if(e.data.err==1){
                             alert("no error");
                        } else {
                             alert("error are there");
                    });
                });

Answer 3

You could return something like {"error": "1"} or {"error": "0"} from the server instead (meaning, put something more readable into a JSON response). This makes the check easier since you have something in data.

PHP:

if(isset($_POST['submit'])){
    $name = trim($_POST['name'];
    $email = trim($_POST['email'];  

    //no any error
    return json_encode(array("error" => 0));
} else {
    return json_encode(array("error" => 1));
}

JavaScript:

jQuery('input#frmSubmit').submit(function(e) {
        //code
        var hasError = false;

        if(!hasError) {
                var formInput = jQuery(this).serialize();
                jQuery.post(jQuery(this).attr('action'),formInput, function(data){
                var myData = data;

                if(myDate.error == 1) {//or "1"
                //do something here
                } else {
                //do something else here when error = 0
                }

                });
            }        
$("form#basicform").submit();       
        return false;


    });