JavaScript object terms
JavaScript is an object-based language. To understand how to interact with the document object model you work with in JavaScript, you need to understand some basic object-related terms. The following table shows the ones you’re likely to find most useful:
| Term | JavaScript example |
|---|---|
| An object is a thing (noun). | A button is an object. |
| You can describe an object with adjectives (properties). |
A button object has a name and a type. |
| An object can do things (methods). | A button object can click(). |
| An object can respond to events (event handlers). | A button can recognize when it’s been clicked (onClick). |
Create a hyperlink, load a web page, and more with JavaScript
JavaScript helps you include all sorts of fun and interactive elements on a Web page, and the following table shows you how to do the kinds of tasks you want to be able to do with JavaScript. Whether you want to load a Web page or copy some code, check for the how-to here:
| To Do This | Do This in Navigator | Do This in Internet Explorer | |
|---|---|---|---|
| Load a JavaScript-enabled Web page | Double-click on the Navigator icon of a file on your machine; or File→Open Page |
File→Open | |
| Look at someone else’s JavaScript code | View→Page Source | View→Source | |
| Find a JavaScript-related news group | Window→ Mail & Newsgroups | Tools→Mail and News→Read News | |
| Copy and paste someone else’s JavaScript code | Ctrl+C to copy; Ctrl+V to paste | Ctrl+C to copy; Ctrl+V to paste | |
| Create a hyperlink | <A> . . . </A> | <A> . . . </A> | |
| Create an HTML form | <FORM> . . . </FORM | <FORM> . . . </FORM |
Troubleshooting JavaScript
JavaScript is a wonderful tool to use to create interesting and interactive Web pages, but every once in a while nothing works and you have no idea where to start to get things moving again. Not to worry; take a look at the following list for hints on what to do to get back on track (try them in this order):
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Is your Web browser installed and configured correctly, including your communications stuff?
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Is JavaScript enabled?
From Navigator: Choose Edit→Preferences→Advanced→Scripts & Plugins and select the Enable JavaScript For Navigator check box.
From Internet Explorer:
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Choose Tools→Internet Options and click the Security tab
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Click the Custom Level button
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Scroll down until the Scripting category appears
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Select the Enable radio button for these options: Active Scripting; Allow Paste Operations Via Script; and Scripting of Java Applets
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Are all your JavaScript statements between <SCRIPT> and </SCRIPT> tags (except JavaScript statements attached to event handlers, which don’t have to be)?
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Does your HTML file work as it should by itself if you delete your JavaScript statements?
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Do the names of your JavaScript variables all start with an alphabetic character (or an underscore)?
JavaScript basic cross-browser document object model
Like any other language, JavaScript has its own grammar and syntax — rules you need to follow to be understood. The following document object hierarchy lists the built-in objects you can work with in client-side JavaScript, along with their relationships to each other:
