Friday 9 August 2013

Automatically log users into your website using HTML5 Local Storage

So your users has been registered. They have gone through the pain of logging in on a mobile phone and you want them to authenticate more easily next time round, so that they don't give up on using your web app.

The solution : HTML5 Local Storage. In the code below, I take the username and password, and put them in localstorage variables. When the (login) page is visited again, I check to see if those localstorage variables exist. If they do, I add them as values to the username and password field, and perform a submit.

Enjoy!

<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<meta http-equiv="X-UA-Compatible" content="IE=edge,chrome=1">
<title>HTML5 Save Password</title>
<!--[if IE]>
<script src="html5.js"></script>
<![endif]-->
<script src="jquery.min.js"></script>
</head>
<body>
<form method="POST" action="set.php">
<label for"username">Username</label>
<input name="username" type="email" />
<label for"password">Password</label>
<input name="password" type="password" />
<input type="submit" />
</form>
<script>
(function()
{
u = false;
p = false;
if(localStorage.getItem('username') != null)
{
$('form input[name=username]').val(localStorage.getItem('username'));
u = true;
}
if(localStorage.getItem('password') != null)
{
$('form input[name=password]').val(localStorage.getItem('password'));
p = true;
}
if((u == true) && (p == true))
{
$('form').submit();
}
$('form').submit(function()
{
localStorage.username = $('form input[name=username]').val();
localStorage.password = $('form input[name=password]').val();
});
})();
</script>
</body>
</html>

Thursday 1 August 2013

HTML5 contenteditable save, re-save and save again

The HTML5 contenteditable attribute is really useful, but when you've got my typing skills, you'd really like to keep saving as you go. In the example below I'm writing to a text file for simplicity. I've got a few things going on.

  • If the text file exists or has data in there, I use it. Otherwise, the editable paragraph holds a default string.
  • I use a form submit to kick off a jQuery event.
  • The jQuery function calls a PHP script to write the contents of my editable paragraph to the file.

This way I can keep pressing the submit button as I go, which will just update the text file with the current editable paragraph contents.

Here's the code.
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<title>Editable jQuery save</title>
<!--[if IE]>
<script src="http://html5shim.googlecode.com/svn/trunk/html5.js"></script>
<![endif]-->
<link rel="stylesheet" href="http://meyerweb.com/eric/tools/css/reset/reset.css" />
<script src="http://www.google.com/jsapi"></script>
<script>
google.load("jquery", "1");
</script>
</head>
<body>
<p id="content" contenteditable="true">
<?php
$text = file_get_contents('test.txt');
if(!empty($text))
{
echo $text;
}
else
{
echo 'Put some text here.';
}
?>
</p>
<form>
<input type="submit" />
</form>
<script>
(function()
{
$('form').submit(function()
    {
        $.post('set.php',
        {
            content:$('#content').text()
        }, function(data)
        {
        if(data)
        {
        console.log(data)
        }    
        });
        return false;
    });
})();
</script>
</body>
</html>

And set.php

<?php
if(isset($_POST['content']))
{
file_put_contents('test.txt', $_POST['content']);
}
else
{
echo 'write was not successful';
}
?>

Heredoc in PHP to reduce a lot of echo calls

Heredoc is a way of building strings for output. Funnily enough I found there was a mistake in some of the coding on the Wikipedia page, but I won't hold that against them. Also, in some of the examples I've come across on the web, they don't seem to recognise an important feature of heredoc. That is, it also provides HTML output.

Below is some example PHP code with the correct syntax, use of variables and HTML. That should speed things up a bit.

<?php
$recipient = 'Mick';
$sender = 'Johnnie';
$x = <<<EOF
Dear $recipient,
I wish you to leave Sunnydale and never return.<br />
Not Quite Love,
$sender
EOF;
echo $x;
?>