JavaScript Programmer's Reference

by Christian MacAuley (Conducted by)

Overview

Get essential programming information at your fingertips! You'll learn to use JavaScript to create customized, interactive Web sites and get quick tips for implementing JavaScript across different browser platforms. This handy guide offers expert tips, language verification, and cross-platform instruction--making this the perfect companion for the serious coder.

Product Details

ISBN-13:	9780072192964
Publisher:	McGraw-Hill/Osborne Media
Publication date:	09/11/2001
Series:	Programmer's Reference
Pages:	288
Product dimensions:	5.59(w) x 8.53(h) x 0.70(d)

About the Author

Christian MacAuley is a web coder, designer, writer, and trainer. Her extensive experience as a JavaScript coder in the streaming media industry has garnered her clients such as PSINet, eStackig, and TV on the Web, among others. Christian's articles about web design and coding have appeared in Web Review and ArtToday. Christian is also the author of Palm Handhelds for Visual Learners (VisiBooks 2001).

Paul Jobson has been building web sites since 1994 and has extensive experience coding client-side JavaScript, Dynamic HTML, and Perl. He is currently contracting for a Fortune 50 company in the DC Metro area.

Read an Excerpt

Chapter 1: Core JavaScript

This chapter discusses JavaScript's core language conventions, including case sensitivity, keywords, data types, reserved words, and operators to get you rolling if you're new to JavaScript.

Language Conventions

Case Sensitivity

Core JavaScript language is case sensitive. This means keywords, variables, function names, or any other identifiers must contain exactly the same letters in the same case. The variable SomeVariable is not the same as SOMEVARIABLE, which is not the same as somevariable.

Microsoft's Internet Explorer browser is the only deviant from this rule. In Internet Explorer, Core JavaScript is case sensitive, but any objects, and their methods and properties, that are added by the Client-Side JavaScript are not case sensitive. For example, Date ( ) and Math () are Core JavaScript functions, and therefore it is invalid to write them as date (), DATE (), Math (), or mAth () . On the other hand, the form object is part of Client-Side JavaScript, and therefore it is valid to write it as window. form or window. FORM or window. Form. Remember, these rules apply to Internet Explorer only and it's not good practice to ignore cases.

Code Formatting

Line Breaks and Whitespace

JavaScript ignores line breaks and whitespace, except in strings and tokens. Whitespace represents a space or tab. Tokens are defined as keywords, variable names, numbers, function names, or some place that you wouldn't want a line break or whitespace. A token could be the number 2 002 ; if you added a space, the numbers 200 2 would be considered two tokens.

Semicolons

JavaScript, like many programming languages, has semicolons at the end of statements. Still, JavaScript does not require you to put a semicolon at the end of a statement. Each of the following statements is valid:

ThisMonth = "August" 
someyear = "2022"; 
nextnum = 33; 
                       testvalue = 300
					   

If there are several statements on one line, you must use semicolons:

thisyear = "2001"; 
othernum = 100;

Even though semicolons are optional, it is better coding practice not to omit them.

Comments

JavaScript comments are simply notes within the code-and they are not part of the program. Developers (such as you) generally use comments to add notes to the code for later reference. There are two forms of comments in JavaScript. Line comments begin with / / and end with a line break, and multiline comments begin with / * and end with * / . Several lines may fall between these symbols.

// This is a comment 
num = S; // Comments may follow a line of code. 
/* Comments may span several lines, 
as long as you use this kind of commenting */

Literals and Identifiers

A literal represents a value in JavaScript. Literals are fixed values, not variables, which you define. Several types of literals are integer literals, octal literals, hexadecimal literals, and string literals.

Reserved Words

In JavaScript there are several groups of words that fall into the "reserved word" category. Reserved words are words that you should not use as identifiers. You may not use any JavaScript keywords, shown in Table 1-1. JavaScript keywords are pan of the language syntax, so they should be avoided. Also, Java keywords, displayed in Table 1-2, should be avoided. Java keywords are not yet used in JavaScript, but future versions of JavaScript may use them. Table 1-3 lists other identifiers to be avoided-these are names of data types, functions, and variables that are predefined by Client-Side JavaScript. Since Internet Explorer is not case sensitive, all keywords in Table 1-2 should be avoided in lowercase and uppercase. Finally, there are words reserved for possible future extensions to the ECMA-262 standard, which are shown in Table 1-4.

Data Types

Numbers

Numbers are basic data types; numeric literals may be integer or floating point; and integers may be decimal, octal, or hexadecimal. JavaScript does not make a distinction between floating-point and integer values; JavaScript recognizes all numbers as floating-point values. These floating-point numbers may be represented as large as +/- 1.7976931348623157x10³⁰⁸ and as small as +/- 5x10^-324.

Integer Literals

Integer literals are represented by Base-10 numbers, which are positive or negative numbers that do not begin with a zero. Integer literals never have decimals, for example...

Table of Contents

	Acknowledgments	xiii
	Introduction	xiii
1	Core JavaScript	1
	Language Conventions	1
	Case Sensitivity	1
	Code Formatting	1
	Literals and Identifiers	2
	Reserved Words	2
	Data Types	5
	Numbers	5
	Special Numeric Values	7
	Strings	7
	Variables	9
	"Untyped" Variables	9
	Declaring Variables	9
	Operators	10
	JavaScript Operators	13
	Operands	13
	Operator Precedence	13
	Operator Associativity	14
	Types of Operators	15
2	Statements and Control Structures	27
	Statements	27
	Expression Statements	27
	Compound Statements	27
	var	28
	function	28
	return	28
	with	28
	import and export	29
	The Empty Statement	29
	try ... catch	30
	Control Structures	30
	Conditional	30
	Loops	33
3	Functions and Objects	37
	Functions	37
	Defining Functions	37
	Executing Functions	38
	Nested Functions	38
	Manipulating Functions as Data	39
	Objects	43
	A Prototype-Based Language	43
	Defining Objects	44
	The Object Superclass	45
	Using Object-Oriented JavaScript	48
4	Core Objects and Functions	51
	Array	51
	Creating Arrays	53
	Array Methods and Properties	54
	Multidimensional Arrays	60
	Boolean	61
	Creating Boolean Objects and Values	61
	Boolean Methods	62
	Date	63
	The Date Constructor	67
	Date Methods	68
	eval ()	81
	Math	82
	Math Methods and Properties	84
	MimeType	92
	MimeType Properties	94
	Number	94
	The Number Constructor	95
	Number Methods and Properties	95
	parseFloat ()	98
	parseInt ()	98
	RegExp	99
	Defining Regular Expressions	99
	Pattern Matching	100
	RegExp Methods	108
	RegExp Object	111
	String	113
	Creating Strings	116
	String Methods and Properties	116
5	JavaScript in the Browser: Client-Side Objects, Methods, and Properties	129
	Embedding JavaScript in HTML Pages	129
	[left angle bracket]Script[right angle bracket] Tags	129
	URL	131
	JSS	132
	Entities	132
	The Document Object Model	133
	The navigator Object	133
	navigator.appCodeName	135
	navigator.appMinorVersion	136
	navigator.appName	136
	navigator.appVersion	136
	navigator.cookieEnabled	136
	navigator.cpuClass	137
	navigator.javaEnabled()	138
	navigator.language	138
	navigator.mimeTypes[]	138
	navigator.online	140
	navigator.oscpu	140
	navigator.platform	140
	navigator.plugins	140
	navigator.product	142
	navigator.productSub	142
	navigator.systemLanguage	143
	navigator.userAgent	143
	navigator.userLanguage	143
	navigator.vendor	143
	navigator.vendorSub	144
	The Event Object (Events and Event Handling)	144
	event.altKey, event.ctrlKey, event.shiftKey	144
	event.bubbles	145
	event.button	145
	event.cancelable	145
	event.cancelBubble	146
	event.clientX, event.clientY	146
	event.currentTarget	146
	event.data	146
	event.eventPhase	146
	event.fromElement	146
	event.height	146
	event.keyCode	147
	event.layerX, event.layerY	147
	event.modifiers	147
	event.offsetX, event.offsetY	147
	event.pageX, event.pageY	147
	event.reason	147
	event.returnValue	148
	event.screenX, event.screenY	148
	event.srcElement	148
	event.srcFilter	148
	event.target	148
	event.toElement	148
	event.type	148
	event.TYPE	149
	event.which	149
	event.width	149
	event.x, event.y	149
	The window Object	150
	window._content	157
	window.alert()	157
	window.atob() and window.btoa()	157
	window.back()	157
	window.blur()	157
	window.captureEvents()	158
	window.clearInterval()	158
	window.clearTimeout()	159
	window.close()	159
	window.closed	159
	window.confirm()	159
	window.crypto	159
	window.dialogArguments	159
	window.dialogHeight	160
	window.dialogLeft	160
	window.dialogTop	160
	window.dialogWidth	160
	window.disableExternalCapture()	160
	window.document	160
	window.enableExternalCapture()	161
	window.escape() and window.unescape()	161
	window.event	161
	window.execScript	161
	window.find()	161
	window.focus()	162
	window.forward()	162
	window.frames[]	162
	window.history	162
	window.home()	162
	window.innerHeight	162
	window.innerWidth	162
	window.length	163
	window.location	163
	window.locationbar	163
	window.menubar	163
	window.moveBy()	163
	window.moveTo()	163
	window.name	163
	window.navigate()	164
	window.offscreenBuffering	164
	window.onblur	164
	window.ondragdrop	164
	window.onerror	164
	window.onfocus	164
	window.onload	164
	window.onmove	165
	window.onresize	165
	window.onunload	165
	window.open()	165
	window.opener	167
	window.outerHeight	167
	window.outerWidth	167
	window.parent	167
	window.personalbar	167
	window.print()	168
	window.prompt()	168
	window.releaseEvents()	168
	window.resizeBy()	168
	window.resizeTo()	168
	window.routeEvents()	169
	window.screen	169
	window.screenX	169
	window.screenY	169
	window.scroll()	169
	window.scrollbars	169
	window.scrollBy()	170
	window.scrollTo()	170
	window.self	170
	window.setHotkeys()	170
	window.setInterval()	170
	window.setResizable()	171
	window.setTimeout()	171
	window.setZOptions()	171
	window.showHelp()	172
	window.showModalDialog() and window.showModelessDialog()	172
	window.sidebar	173
	window.status	174
	window.statusbar	174
	window.stop()	174
	window.toolbar	174
	window.top	174
	window.window	174
	window.XOffset	174
	window.YOffset	175
	Document Properties	175
	document.activeElement	179
	document.all	179
	document.alinkColor, document.bgColor, document.fgColor, document.linkColor, document.vlinkColor	180
	document.anchors[]	181
	document.applets[]	181
	document.attributes	181
	document.body	181
	document.characterSet	182
	document.childNodes	182
	document.clear()	182
	document.close()	183
	document.cookie	183
	document.createElement()	183
	document.createStyleSheet()	183
	document.defaultCharset	183
	document.domain	184
	document.elementFromPoint()	184
	document.embeds[]	184
	document.execCommand()	184
	document.expando	184
	document.fileCreatedDate	187
	document.fileModifiedDate	187
	document.fileSize	188
	document.fileUpdatedDate	188
	document.form	188
	document.forms[]	235
	document.frames[]	235
	document.getSelection	235
	document.height	236
	document.images[]	236
	document.lastModified	236
	document.links[]	236
	document.mimeType	236
	document.open()	236
	document.parentWindow	236
	document.queryCommandEnabled()	237
	document.queryCommandIndeterm()	237
	document.queryCommandState()	237
	document.queryCommandSupported()	237
	document.queryCommandText()	237
	document.queryCommandValue()	238
	document.readyState	238
	document.referrer	238
	document.scripts[]	238
	document.selection	238
	document.styleSheets[]	239
	document.title	239
	document.URL	239
	document.width	239
	document.write()	239
	document.writeln()	239
	Appendix
	JavaScript Versions Chart	241
	Character Charts	242
	Event Handlers Chart	251
	The Authors' Bookmarks	253
	Web Browsers	255
	Country Codes	255
	JavaScript Security	258
	JavaScript's Inherent Security	258
	Security by Obscurity Doesn't Work	259
	Index	261