introduction to javascript. introduction what is it? how does it work? what is java? learning...
DESCRIPTION
What is JavaScript? Browsers have limited functionality Text, images, tables, frames JavaScript allows for interactivity Browser/page manipulation Reacting to user actions A type of programming language Easy to learn Developed by Netscape Now a standard exists – standards/ECMA-262.HTMTRANSCRIPT
Introduction to JavaScript
IntroductionWhat is it?How does it work?What is Java?Learning JavaScript
JavaScript Statements JavaScript and HTML forms
What is JavaScript?Browsers have limited functionality
Text, images, tables, framesJavaScript allows for interactivityBrowser/page manipulation
Reacting to user actionsA type of programming language
Easy to learn Developed by Netscape Now a standard exists – www.ecma-international.org/publications/standards/ECMA-262.HTM
JavaScript Allows InteractivityImprove appearance
Especially graphics Visual feedback
Site navigationPerform calculationsValidation of inputOther technologies
javascript.internet.com
How Does It Work?Embedded within HTML page
View sourceExecutes on client
Fast, no connection needed once loadedSimple programming statements combined with
HTML tagsInterpreted (not compiled)
No special tools required
What is Java?Totally differentA full programming languageMuch harder!A compiled languageIndependent of the webSometimes used together
Learning JavaScriptSpecial syntax to learnLearn the basics and then use other people's
(lots of free sites)Write it in a text editor, view results in browserYou need to revise your HTML You need patience and good eyesight!
JavaScript Statements<html><head><title>My Page</title></head><body><script language="JavaScript">
document.write('This is my first JavaScript Page');
</script></body></html>
Note the symbol for line continuation
JavaScript Statements<html><head><title>My Page</title></head><body><script language=“JavaScript">
document.write('<h1>This is my first JavaScript Page</h1>');
</script></body></html>
HTML writteninside JavaScript
JavaScript Statements<html><head><title>My Page</title></head><body><p><a href="myfile.html">My Page</a><br /><a href="myfile.html"onMouseover="window.alert('Hello');">My Page</A></p></body></html>
JavaScript writteninside HTML
An Event
Example Statements<script language="JavaScript">window.prompt('Enter your name:','');</script>
<form><input type="button" Value="Press" onClick="window.alert('Hello');">
</form>
Another event
Note quotes: " and '
HTML Forms and JavaScriptJavaScript is very good at processing user input
in the web browserHTML <form> elements receive inputForms and form elements have unique names
Each unique element can be identified Uses JavaScript Document Object Model (DOM)
Naming Form Elements in HTML
<form name="addressform">Name: <input name="yourname"><br />Phone: <input name="phone"><br />Email: <input name="email"><br /></form>
Forms and JavaScriptdocument.formname.elementname.valueThus:
document.addressform.yourname.valuedocument.addressform.phone.valuedocument.addressform.email.value
Using Form DataPersonalising an alert box
<form name="alertform">Enter your name:<input type="text" name="yourname"><input type="button" value= "Go" onClick="window.alert('Hello ' + document.alertform.yourname.value);">
</form>
TipsCheck your statements are on one lineCheck your " and ' quotes matchTake care with capitalisationLay it out neatly - use tabsRemember in the workbook denotes a
continuing lineBe patient
Presentation slides adapted from scom.hud.ac.uk/scomsjw/Web%20Authoring%20Module/Lecture%20Slides/ introjs.ppt