JavaScript

JavaScript is the default scripting language in HTML5 and in all modern browsers!

JavaScript Data Types

String, Number, Boolean, Array, Object, Null, Undefined

"Everything" in JavaScript is an Object.

JavaScript Errors - Throw and Try to Catch

try {
var x=document.getElementById("demo").value;
if(x=="") throw "empty";
if(isNaN(x)) throw "not a number";
if(x>10) throw "too high";
if(x<5) throw "too low";
} catch(err) {
y.innerHTML="Error: " + err + ".";
}

Boolean Object

0, -0, null, "", false, undefined, NaN --- false

RegExp Object

test() method searches a string for a specified value, and returns true or false, depending on the result.

exec() method searches a string for a specified value, and returns the text of the found value. If no match is found, it returns null.

JavaScript HTML DOM

Finding HTML Elements

Finding HTML elements by id
Finding HTML elements by tag name
Finding HTML elements by class name(does not work in Internet Explorer 5,6,7, and 8)
Finding HTML elements by HTML object collections(document.forms["frm1"], anchors,images,links)]

Changing the HTML

changing the output stream: document.write(Date());

changing html content: document.getElementById(id).innerHTML=new HTML

changing the value of attribute: document.getElementById(id).attribute=new value

Changing HTML Style

document.getElementById(id).style.property=new style

The Browser Object Model

The Window Object

var w=window.innerWidth|| document.documentElement.clientWidth|| document.body.clientWidth;

var h=window.innerHeight|| document.documentElement.clientHeight|| document.body.clientHeight;

window.open() - open a new window
window.close() - close the current window
window.moveTo() -move the current window
window.resizeTo() -resize the current window

Window Screen

Window Location

location.hostname returns the domain name of the web host
location.pathname returns the path and filename of the current page
location.port returns the port of the web host (80 or 443)
location.protocol returns the web protocol used (http:// or https://)
location.href returns the the URL of the current page.
location.assign() method loads a new document.

Window History

history.back() - same as clicking back in the browser
history.forward() - same as clicking forward in the browser

Window Navigator

The information from the navigator object can often be misleading, and should not be used to detect browser version.

Since different browsers support different objects, you can use objects to detect browsers.

if (window.opera) {...some action...}

Popup Box

alert("sometext");

confirm("sometext");

prompt("sometext","defaultvalue");

JavaScript Timing Events

setInterval("function",milliseconds) - executes a function, over and over again, at specified time intervals
setTimeout("function",milliseconds) - executes a function, once, after waiting a specified number of milliseconds
clearInterval(intervalVariable) - stop the execution

JavaScript Cookie

A cookie is a variable that is stored on the visitor's computer. Each time the same computer requests a page with a browser, it will send the cookie too. With JavaScript, you can both create and retrieve cookie values.

getCookie("username"); setCookie("username",username,365);

JavaScript Objects Reference

The references describe the properties and methods of each object, along with examples.

Browser Objects Reference

The references describe the properties and methods of each object, along with examples.

HTML DOM Reference

The references describe the properties and methods of the HTML DOM, along with examples.

HTML Element Objects Reference

The references describe the properties and methods of each HTML object, along with examples.