showing alert box using php and javascript

Question

if (!(isset($_POST['fullname']) && strlen($_POST['fullname']))) {
  echo 
  "<script type=\"text/javascript\">".
  "window.alert('You must enter your full name.');".
  "</script>"; 

   exit;             
}

The above code is in the register.php file. I have html form in the index.html. when i post the form without full name. it displays alert but page gets stuck at register.php (blank page.) i want to display the alert on index.html page or atleast get redirected to index.html. how to do it???

Tushar Gupta - curioustushar · Accepted Answer · 2013-10-31 04:39:52Z

3

Try window.location.href = '/index.html inside script

if (! (isset($_POST['fullname']) && strlen($_POST['fullname']))) {
    echo "<script type=\"text/javascript\">window.alert('You must enter your full name.');window.location.href = '/index.html';</script>"; 
   exit;
}

answered Oct 31, 2013 at 4:39

Tushar Gupta - curioustushar

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Comments

jondinham · Accepted Answer · 2013-10-31 04:41:10Z

0

Do it this way:

if (!(isset($_POST['fullname']) && strlen($_POST['fullname']))) {
  echo 
  "<script type=\"text/javascript\">".
  "window.alert('You must enter your full name.');".
  "top.location = 'index.html';".
  "</script>"; 

   exit;             
}

answered Oct 31, 2013 at 4:41

jondinham

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3 Comments

ElGavilan Over a year ago

This will cause the redirect to occur after the alert is dismissed, which may confuse users (this may be his desired effect though, who knows). I would do the redirect server side.

ElGavilan Over a year ago

Maybe so, but they still need to learn. Noobs can't stay noobs forever

HungryDB Over a year ago

Yeah, still learning. But it'll be nice if you do constructive critisism.

ElGavilan · Accepted Answer · 2013-10-31 04:41:12Z

0

Your exit command is stopping execution, that is why it gets stuck at register.php.

If you want to redirect to another page: http://www.cyberciti.biz/faq/php-redirect/

answered Oct 31, 2013 at 4:41

ElGavilan

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Comments

Ronak Patel · Accepted Answer · 2013-10-31 04:42:03Z

0

Do 1 thing.. Put this if condition in the same page. and submit your form on the same page. it's better idea. if you don't need register.php file for different reason. It can be done by

windows.location("index.php").

but it's now good way.

answered Oct 31, 2013 at 4:42

Ronak Patel

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Comments

srain · Accepted Answer · 2013-10-31 04:43:13Z

0

<?php
if (!(isset($_POST['fullname']) && strlen($_POST['fullname']))) {
    echo
        "<script type=\"text/javascript\">".
        "window.alert('You must enter your full name.');".
        'window.location.href="index.html";'.
        "</script>";

    exit;
}

answered Oct 31, 2013 at 4:43

srain

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Comments

Sean Johnson · Accepted Answer · 2013-10-31 04:44:51Z

0

You'll want to do this completely client side - a trip to the server isn't even necessary in order to determine whether or not the fullname field was filled out.

Try something like the following on your registration page:

<form id="myform" action="register.php" method="post">
    Full Name: <input type="text" name="fullname" />
    <input type="submit" value="Submit" />
</form>

<script type="text/javascript">
document.getElementById('myform').onsubmit=function(){
    if(!this.fullname.value) {
        alert("You must enter your full name")
        //stop form submission
        return false
    }
    //continue on to register.php
    return true
}
</script>

Working JS Fiddle:

http://jsfiddle.net/GAk8C/

answered Oct 31, 2013 at 4:44

Sean Johnson

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Comments

Sean Johnson · Accepted Answer · 2013-10-31 04:46:07Z

0

When you are posting a form using PHP, it redirects the browser to that page. Why not alert the error message before submitting the form? Here is a short example:

<form name="contactForm" action="register.php">
    <label for="name" id="name_label">Name</label>  
    <input type="text" name="name" id="name" />  
    <input type="submit" name="submit" class="button" id="submit_btn" value="Send" />
</form>

<script>
    $(function() {  
        $('#contactForm').on('submit', function() {  
            // validate and process form here
            if( !$("#name").val() ) {  
                alert('You must enter a valid name!');
                return false;
            }
        });  
    });
</script>

edited Oct 31, 2013 at 4:46

Sean Johnson

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answered Oct 31, 2013 at 4:43

Pastor Bones

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4 Comments

ElGavilan Over a year ago

Client side validation is always good form, but a completely sound application must always validate on the server side after the fact too.

Pastor Bones Over a year ago

Very good point! +1 for redundant security, but merely wanted to open the OP's eyes to JQuery form validation.

HungryDB Over a year ago

yeah, i heard from somewhere that i shouldn't do any validation with JS, user has control over JS turn on/off. is that true?? (totaly new to JS and jquery)

Pastor Bones Over a year ago

@HungryDB - that is true, but client side validation can make for a cleaner user experience and as ElGavilan pointed out above you should always validate on the server side as well to prevent any hacking.

Vishal · Accepted Answer · 2013-10-31 04:52:56Z

0

I Think You are doing this for validation of the field. It is better to do the simple validation in index.html page itself. use in your html code in the index.html pge add the folloimg in your submit button

<input type="submit" name="submit" value="yourvalue" onclick="return validateName()">

And use the javascript validation method as

<script language="javascript" >
function validateName(){
if(document.getElementById("idOfFirstNameField").value==""){
alert("Please enter your name");
document.getElementById("idOfFirstNameField").focus();
return false;   
    }   

    }
</script>

answered Oct 31, 2013 at 4:52

Vishal

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Comments

Ashish Jain · Accepted Answer · 2013-10-31 04:53:23Z

0

Better way, you can give javascript on index.html itself. so when user will not put fullname then it will not redirect to register.php. it will stay on same page with alert error message means on index.html

in head of HTML you put like that

<head>
function validate(){
     fname=document.getElementByID('fname').value;
     if (fname==""){
         alert("Please provide full name.");
         return false;
     }else{
         window.location.href = 'register.php';
     }
}
</head>
<body>
      <form name="adminform" src="register.php" onsubmit="return validate();">
      <input type="text" id="fname" name="fname" value=""/>
      </form>
</body>

if user put full name then it will redirect to register.php

answered Oct 31, 2013 at 4:53

Ashish Jain

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Comments

Javi Ps · Accepted Answer · 2015-12-02 09:52:35Z

0

The way i do it. In register.php file:

<?php session_start();

if((empty($_POST['name'])) || (empty($_POST['email'])) || (empty($_POST['subject'])) || (empty($_POST['message']))) {
    $_SESSION['mensaje']="<script language=\"javascript\">alert('All fields are mandatory')</script>";
    header("Location: ../contact.php");
    exit;
  }

And in the first lines of the file that you will redirect in case of error (in this case contact.php)

<?php session_start();
if(isset($_SESSION['mensaje'])){
  echo $_SESSION['mensaje'];
}
session_destroy();?>
<!DOCTYPE html>

Also you can use the same way to show a success message. Hope it helps.

edited Dec 2, 2015 at 9:52

answered Dec 6, 2014 at 16:12

Javi Ps

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