<html> <!-- Required for all HTML pages --> <head> <title>The Top Bar Title</title> </head> <body> Some information <!-- A Comment Tag --> </body> </html> <!-- Closing tag, required -->Example 1
<html> <!-- Required for all HTML pages -->
<head>
<title>The Top Bar Title</title>
</head>
<body>
Some information
<br> <!-- A line break -->
<!-- A Comment Tag -->
<? // Denotes the start of PHP processing
echo "The Date and Time is: "; // print a string, end with a semicolon
$mydata = "July 29, 2004"; // Assign a variable
echo $mydata; // print the string variable
?>
</body>
</html> <!-- Closing tag, required -->
Example 2
<?PHP
echo("Hello World!\n");
?>
As you can see, PHP is very similar to many other languages. There are a bunch of built-in functions (such as echo) and arguments are passed into functions through paranthesis. Strings are put into single or double quotes and the newline char is the \n. Lines of code are ended with semi-colons.
<?PHP $myString = "hello world\n"; echo($myString); $myInteger = 1003; echo($myInteger . "\n"); $somethingelse = false; echo($somethingelse . "\n"); ?>More Information:
<?PHP
$aValue = 0;
$aValue++;
echo("aValue now = " . $aValue . "\n");
$aValue = $aValue + $aValue;
echo("aValue now = " . $aValue . "\n");
// % + - * / ++ -- and so on, same as in Processing/Java
?>
More Information:
<?PHP
// If Statement
$aValue = 0;
if ($aValue == 0)
{
echo("aValue is 0");
}
else if ($aValue == 1)
{
echo("aValue is 1");
}
else if ($aValue >= 2)
{
echo("aValue is greater than or equal to 2");
}
else
{
echo("aValue something else");
}
echo("\n");
// Other Logical Operators ==, >, <, >=, <=, ||, &&
// For loop
for ($i = 0; $i < 10; $i++)
{
echo("\$i = $i\n");
}
// Also While
?>
More Information:
<?PHP
// Pretty normal array
$anArray = array();
$anArray[0] = "Something";
$anArray[1] = "Something Else";
for ($i = 0; $i < sizeof($anArray); $i++)
{
echo($anArray[$i] . "\n");
}
// Key Value Map
$anotherA = array("somekey" => "somevalue", "someotherkey" => "someothervalue");
$keys = array_keys($anotherA);
$values = array_values($anotherA);
for ($i = 0; $i < sizeof($keys); $i++)
{
echo($keys[$i] . " = " . $values[$i] . "\n");
}
?>
More Information:
<?PHP
function myFunction($somearg)
{
// You would do something here
return "You passed in $somearg";
}
$passing_in = "Hello World";
$return_value = myFunction($passing_in);
echo($return_value);
echo("\n");
?>
More Information:
<?PHP
class MyClass
{
var $myClassVar;
function set_var($new_var)
{
$this->myClassVar = $new_var;
}
function get_var()
{
return $this->myClassVar;
}
}
$aClass = new MyClass;
$aClass->set_var("something");
echo("Var: " . $aClass->get_var() . "\n");
?>
Classes and Objects in PHP are very similar to Java/Processing. Syntactically though they don't use the "." operator, instead using "->". Also, in the class definition you need to use the "this" keyword.
<?PHP
$somevar = NULL;
if (isset($somevar))
{
echo("somevar is set");
}
else
{
echo("somevar is NOT set");
}
?>
JavaScript is a scripting language most often used for client-side web development. It was the originating dialect of the ECMAScript standard.
(From Wikipedia JavaScript)
<html>
<head>
<script type="text/javascript">
alert("Hi There!");
</script>
</head>
<body>
Nothing here..
</body>
</html>
It can also be a separate file located on a webserver:
<html> <head> <script type="text/javascript" SRC="ascript.js"></script> </head> <body> Nothing here.. </body> </html>or both:
<html>
<head>
<script type="text/javascript" SRC="ascript.js"></script>
<script type="text/javascript">
alert("Hi There!");
</script>
</head>
<body>
Nothing here..
</body>
</html>
Variables
var avariable; // Declares a variable called avariable avarable = 15; // Assigns 15 to that variableVariables are not generally "typed".. You can do this:
var anothervariable = "My Name Is Shawn"; alert(anothervariable); anothervariable = 15; alert(anothervariable);Comments
// single line comment /* multiline comment */Comparison, Conditionals and Loops
var what = true;
var now = 5;
if (what == now)
{
// Then do this
}
else if (1 != 1)
{
// Or this
}
else
{
// Those weren't true.. Let's loop
for (var i = 0; i < now; i++)
{
alert("Counting: " + i);
}
}
Built-In Functions
function dosomething(somedata)
{
var whattosay = "Hi there " + somedata + " , nice to meet you!";
alert(whattosay);
}
As you can see, the + symbol string concatenation.
dosomething("shawn");
or
<input type="button" name="name" value="blah" onClick="dosomething(this.value);" />
<script type="text/javascript">
function changeIt()
{
var thediv = document.getElementById('mydiv');
thediv.innerHTML = "soemthing else";
}
</script>
My Div:
<div id="mydiv">Something</div>
<input type="button" name="changeit" value="Change It" onClick="changeIt();" />
My Div:
<?php echo "Something"; ?>The HTML (named ajax_example.html):
<html>
<head>
<title>AJAX Example</title>
<!-- Load up the AJAX External JavaScript file -->
<script type="text/javascript" src="ajax.js"></script>
<!-- Local Javascript Functions and so on -->
<script type="text/javascript">
// A variable to hold the interval id
var interval = null;
// A function to call our AJAX PHP script
function call_ajax()
{
makeHttpRequest('ajax_example.php',ajax_return);
}
// A function that gets called when ajax returns
function ajax_return(response)
{
document.getElementById("messages").innerHTML = response;
}
// Setup AJAX function, creates a timeout so that we run something periodically
function setup_ajax()
{
// Set interval of 5000 milliseconds
// Keeps going...
interval = setInterval("call_ajax()",5000);
// Only happens once..
//interval = setTimeout("call_ajax()",5000);
}
// Register setup_ajax with the onload event of the window (when it is done loading)..
function addOnLoad()
{
if (window.addEventListener)
{
window.addEventListener('load', setup_ajax, false);
}
else if (window.attachEvent)
{
window.attachEvent('onload', setup_ajax);
}
}
addOnLoad();
</script>
</head>
<body>
<b>Looky here!</b>
<div id="messages" style="overflow: auto; width: 500px; height: 400px;">
Something should pop up here..
</div>
</body>
</html>
It was developed by Jeremie Miller in 1998/1999 and is an open standard based specification for XML based messages. The story is that Jeremie was sick of proprietary chat clients (skype, aim/ichat, msn, yahoo, icq and so on) and having them all open to communicate with those he was working or conversing with. He developed this to be an answer to that issue. It has since become very popular with Google utilizing it for their GTalk service.
In some ways it is very similar to IRC in that it is distributed among servers and everyone on the network can talk to everyone else by knowing their ID (servers connect to exchange information when needed). In other ways it is more about IM than group chat although group chat is supported well.
Not just for IM which is presence, buddy list (roster).. Standard XML which can easily be extended for other features.