Javascript Learning Note Two

1. Find HTML elements

Typically, with JavaScript, you need to manipulate HTML elements.
In order to do this, you must first find the element. There are three ways to do this:
HTML element found by ID (This example finds id= "Intro" Element)

var X=document.getelementbyid ("Intro");

Find the HTML element through the tag name (this example finds the element that id= "main" and then finds all the <p> elements in "main")

var X=document.getelementbyid ("main"); var y=x.getelementsbytagname ("P");

Find HTML elements by class name

2. Changing HTML properties

To change the attributes of an HTML element, use this syntax:

document.getElementById (ID). attribute=new value

3. Change HTML style

To change the style of your HTML elements, use this syntax:

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

4. OnLoad and OnUnload Events

The onload and OnUnload events are triggered when the user enters or leaves the page.
The OnLoad event can be used to detect the browser type and browser version of the visitor and to load the correct version of the Web page based on that information.
The onload and OnUnload events can be used to process cookies.

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Javascript Learning Note Two