Category Archives: JavaScript

JavaScript

01.28.13
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The power of cookies is that they offer persistence


The power of cookies is that they offer persistence. When the document that created or modified a cookie is no longer loaded, the data in the cookie is still there.
Other documents that know about the cookie can access and modify its data, so the data can be shared between documents.
01.28.13
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One potential use for cookies is in online catalogs


One potential use for cookies is in online catalogs. A store with an extensive inventory would not want to put its entire catalog in a single document.
Instead, they would probably break up the catalog into manageable pieces, with each separate document focusing on a particular class of merchandise.
01.28.13
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The user of an online catalog could select items from several pages


The user of an online catalog could select items from several pages. Each page could record the user’s selection in a cookie. When the user was finally ready to send in the order, the cookie would be read back into a form for the user to verify.
The entire list, containing items from several different documents, would then be submitted to the store.
01.28.13
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Using the ability to write frame contents on the fly


Using the ability to write frame contents on the fly, you can also use cookies to remember things about the user and to tailor the contents of your document’s frames to that user.
An example might be an a personalized greeting, combined with an indication of how long it has been since the user last loaded the document.
01.28.13
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Live documents are Web pages that change as time passes


Live documents are Web pages that change as time passes. You can create timers in your code.
When the timer counts down, a JavaScript expression is executed. You can do many things with timers, such as scroll messages on the screen or load a document when the timer counts down.
01.28.13
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JavaScript confers an even greater ability to create a spectacular document


HTML enables you to take plain text and turn it into an attractively laid out document. It also lets you turn the text into an ugly mess that no one would want to read. JavaScript confers an even greater ability to create a spectacular document, and an even greater ability to create a hideous page that no one will want to read.
You can also even crash the browser by using the java script.
01.28.13
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Your Web pages are your personal ambassadors to the world


Your Web pages are your personal ambassadors to the world. They make a statement about you. Naturally, you can’t control everyone’s reaction to your pages; some people simply are not going to take an interest in what you have to say.
But you can take simple steps in terms of the content of your pages and in terms of the presentation of your pages to maximize the impact you want your pages to have.
01.28.13
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If you have a lot of JavaScript code in your pages


If you have a lot of JavaScript code in your pages, the spell checker will probably go ballistic over the code. It will not recognize your variable or function names unless you’ve entered them into the spell checker’s dictionary, which is a practice I do not endorse.
The solution is to make a copy of your page and remove the contents of the <SCRIPT> element before running the copy through a spell checker. Because you’ll be making changes by hand, this should be an iterative process. Of course, you can avoid the iterative process if you have access to software that will merge changes automatically.
01.28.13
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It’s a sad but true fact that not all browsers support JavaScript


It’s a sad but true fact that not all browsers support JavaScript. Readers using popular browsers such as NCSA Mosaic will not benefit from your JavaScript expertise.
.Unless you want to alienate those readers, you need to be sensitive to the needs of the Netscape-deficient. Two major errors to avoid are littering the screen with JavaScript code and leaving a blank page for the reader to ponder.
01.28.13
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The other way of ending a comment is to begin a JavaScript one-line comment


The other way of ending a comment is to begin a JavaScript one-line comment-the kind that starts with // and ends with the end of the source line. Just make sure that the –> is at the end of the comment. As with the first method, browsers that don’t support JavaScript will close the comment that was begun after the <SCRIPT> tag when they see the –> at the end of the comment. Netscape sees it as a routine JavaScript comment.
And the only drawback to this technique is that it forces the </SCRIPT> tag to be on the next source line. If it were on the same line as the one-line comment, it would become part of the comment.