PHP validation for Javascript

Question

I have a new problem. My whole website is written in PHP as well as all validations. Is there a way to do validations in php and then execute javascript like the example bellow?

if (@$_POST['submit']) {
    if ($txt == "") {
        $err = "No comment";
    } 
    else {
        echo "<script type='text/javascript'>
            function myFunction() {
                var txt' = '$txt';
                var dataString = 'txt=' + txt;
                $.ajax({
                  type: 'POST',
                  url: 'ajaxjs.php',
                  data: dataString,
                  cache: false,
                  success: function(php) {
                      alert(php);
                  }
               });
            }
        </script>";
    }
}

<div id="text">
    <form action="" method='POST'>
        <textarea maxlength="2000"></textarea>
        <input type='button' onclick="myFunction()" name='submit' value='post' />
    </form>
</div>

This doesn't work. So I'm wondering how should I do it? I guess forms don't work with javascript, but how do I do it without a form?

What exactly are you expecting as output? You don't use anywhere your javascript function.myFunction — user2560539
– user2560539, Commented Jul 16, 2016 at 20:13
@PeterDarmis Sorry, I posted the wrong core. Updated now. It doesn't work with onclick="myFunction()" either — Menel
– Menel, Commented Jul 16, 2016 at 20:17
@Menel if you're trying to execute a function onsubmit then you might use <form onsubmit="formSubmit();"> and make formSubmit() return false, this is important. — Paper
– Paper, Commented Jul 16, 2016 at 20:19
@Menel you don't need to use php here only jQuery/Javascript is enough — user2560539
– user2560539, Commented Jul 16, 2016 at 20:28
@timmyRS that sounds like something that could solve this for me. How do I make formSubmit() return false? Do I do it at the end of validation in the javascript or? — Menel
– Menel, Commented Jul 16, 2016 at 20:36

score 2 · Accepted Answer · 2016-07-16 23:18:58Z

2

You don't need to use php at all. You can post your textarea data like in the below example.

HTML

<div id="text">
<textarea id="txtArea" maxlength="2000"></textarea>
<button id="btnSubmit" name='submit'>post</button>
</div>

Javascript/jQuery

$("#btnSubmit").on('click',function(e) {
   e.preventDefault();
   var txtValue = $("#txtArea").val();
   if(txtValue.length==0) {
     alert("You have not entered any comments");
   } else {
     $.ajax({
        type: 'POST',
        url: 'ajaxjs.php',
        data: {txt:txtValue},
        cache: false
        })
  .done(function() {
    alert( "success" );
  })
  .fail(function() {
    alert( "error" );
  });    
  }
});

edited Jul 16, 2016 at 23:18

answered Jul 16, 2016 at 20:53

user2560539

Sign up to request clarification or add additional context in comments.

Comments

Ivnhal · Accepted Answer · 2016-07-16 20:19:14Z

1

The solutions is: 1. add function for submit event. 2. call ajax with form fields values as data. 3. do vildation inside php called with ajax request and return status code (valid/not valid) 4. analyse code in js and output error/success message.

answered Jul 16, 2016 at 20:19

Ivnhal

1,0951 gold badge12 silver badges20 bronze badges

Comments

Paper · Accepted Answer · 2016-10-07 23:47:30Z

1

First of all: Your code has a couple of errors.

You are asking if $txt == "" whilst $txt was not visibly set.
Your text area has no name
Your if doesn't ask if empty($_POST["submit"])

Second of all: You mentioned that you want the code to be executed on submit of the form. Therefore you can simple do this:

<form onsubmit="formSubmit();">
    ...
</form>
<script>
function formSubmit()
{
    if(...)
    {
        return true; // Valid inputs, submit.
    }
    return false; // Invalid inputs, don't submit.
}
</script>

The return false is important because if it would miss, the form would be submitted as usual.

edited Oct 7, 2016 at 23:47

answered Jul 16, 2016 at 20:12

Paper

1,3142 gold badges19 silver badges32 bronze badges

Collectives™ on Stack Overflow

PHP validation for Javascript

3 Answers 3

Comments

Comments

Comments

Your Answer

Hot Network Questions

Collectives™ on Stack Overflow

3 Answers 3

Comments

Comments

Comments

Your Answer

Sign up or log in

Post as a guest

Related