JavaScript

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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.

Array object

Boolean object

Date object

Math object

Number object

String object

RegExp object

Global properties and functions

Browser Objects Reference

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

Window object

Navigator object

Screen object

History object

Location object

HTML DOM Reference

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

HTML Document

HTML Element

HTML Attributes

HTML Events

HTML Element Objects Reference

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

Anchor object

Area object

Base object

Body object

Button object

Form object

Frame/IFrame object

Frameset object

Image object

Input Button object

Input Checkbox object

Input File object

Input Hidden object

Input Password object

Input Radio object

Input Reset object

Input Submit object

Input Text object

Link object

Meta object

Object object

Option object

Select object

Style object

Table object

td / th object

tr object

Textarea object