Scripts

1
Chapter 18

• Scripts
• (JavaScript)

2
Quick Overview

• Scripts are tiny programs inside a page
• Allow interaction with page user
• Sometimes called Dynamic HTML
• DHTML
• JavaScript can take a whole semester
• Just the basics for now

3
Two Types of Scripts

• Automatic scripts
• Load/run automatically when the page opens
• Triggered scripts
• Do NOT run as soon as a page opens
• Instead, triggered by some event
• Press button
• Click a link
• Mouse over an area of the page
• etc.

4
Automatic Scripts

• Can be useful when writing advanced scripts
• Printing current date/time on page
• New pop-up message when page opens
• Can be annoying, so be careful

5
Triggered Scripts

• Also known as intrinsic events
• Script runs when user does something
• onclick
• ondblclick
• onmouseover
• See p. 316 317 for entire list of 18
• When user interacts with an element
• ltbodygt lta href...gt ltpgt ltdivgt ltspangt ltimg src...gt
• any element (almost ... see p.448)

6
Triggered Scripts
Easiest example ltspan onclickalert('I like
grapefruit')gt some text lt/spangt
7
Triggered Scripts Hints

• If you need to use an apostrophe in your alert
• backslash it
• onclickalert('Who\'s there?')
• Pay attention to single and double quotes
• If you make a script in an empty element
• ltdivgt lt/divgt
• make sure your CSS forces a width and/or height

8
Buttons

• You can make buttons to run a triggered script
• ltbutton typebutton
• namesomename
• onclickalert('You pushed a button')
• backgroundyellow colorredgt
• Push this button
• lt/buttongt