Saturday, 12 October 2013

PHP form tutotial

An HTML form is a section of a document containing normal content, markup, special elements called controls (checkboxes, radio buttons, menus, etc.), and labels on those controls. Users generally "complete" a form by modifying its controls (entering text, selecting menu items, etc.), before submitting the form to an agent for processing (e.g., to a Web server, to a mail server, etc.)

Methods

The method attribute specifies how to send form-data (the form-data is sent to the page specified in the action attribute).
The form-data can be sent as URL variables (with method="get") or as HTTP post transaction (with method="post").
Notes on GET:
  • Appends form-data into the URL in name/value pairs
  • The length of a URL is limited (about 3000 characters)
  • Never use GET to send sensitive data! (will be visible in the URL)
  • Useful for form submissions where a user want to bookmark the result
  • GET is better for non-secure data, like query strings in Google
Notes on POST:
  • Appends form-data inside the body of the HTTP request (data is not shown is in URL)
  • Has no size limitations
  • Form submissions with POST cannot be bookmarked

How to Cancel PHP form submission using javascript


<?php 

$msg="";

if(isset($_POST['submit']))

{
$msg="ok";//put your code here
}
?>


<html>
<head>
<title>Demo</title>
<script language="javascript">
function demo()
var ob=confirm('sure');
if(ob==true)
{
alert('ok');
return true;
}
else
{
alert('dont leave');
return false;
}
}
</script>
</head>
<body>
<form method="post" action=<?php echo $_SERVER['PHP_SELF']?>  onSubmit="return demo()" >
<input type="submit" name="submit" value="Delete" >
<br>
<span style="font-size:50px;color:#FF0000">
<?php echo $msg; ?>
</span>
</form>
</body>
</html>

Retain form’s control value after submitting the form

Text Box :

<input type="text" name="name" value="<?php echo $_POST['name'];?>"/>

Textarea

<textarea row="5" cols="15" name="msg"><?php echo $_POST['msg'];?></textarea>

Reset or Clear form data after submitting


unset($_POST);