About.com Focus on JavaScript

Convert to Roman Numerals

Sat, 21 Nov 2009 12:41:07 +0000

JavaScript can display the answer in roman numerals

Sometimes displaying a number on your web page as a normal number just doesn't look right. Sometimes it may be more appropriate to display the number on your web page using Roman Numerals instead. This simple Javascript function can handle the conversion of any number between 1 and 3999 into the roman numeral equivalent for you.

Convert to Roman Numerals

Convert to Roman Numerals originally appeared on About.com Focus on JavaScript on Saturday, November 21st, 2009 at 12:41:07.

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Numbers to Words

Fri, 20 Nov 2009 12:35:25 +0000

Convert numbers to Words with JavaScript.

JavaScript does an excellent job of being able to manipulate numbers and even provides some quite advanced mathematical functions. What happens though when you want to print out the result of that manipulation in words rather than numbers? You use a simple function that will do the conversion for you.

Numbers to Words

Numbers to Words originally appeared on About.com Focus on JavaScript on Friday, November 20th, 2009 at 12:35:25.

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Formatting Numbers

Thu, 19 Nov 2009 12:52:40 +0000

The format JavaScript wants to work with isn't always the same as the format you want to display the result in.

To be able to process numbers in JavaScript they must contain nothing except digits and perhaps a period as the decimal point and a dash for a minus sign. If you include anything else then Javascript treats it as a text string instead of a number and so will not allow you to use it in calculations. What would be useful though is a way to take those numbers and apply some formatting to them (comma separators, currency etc.) before displaying the result in our web page. Since this may need to be done for several numbers it is best done using a function and to save you the trouble of working out the JavaScript to do this I have written this function for you.Now updated to correctly handle numbers between 1 and -1.

Formatting Numbers

Formatting Numbers originally appeared on About.com Focus on JavaScript on Thursday, November 19th, 2009 at 12:52:40.

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Starting Values

Wed, 18 Nov 2009 21:45:16 +0000

What does it start with?

In the eleventh form validation tutorial we look at how we can test that a field starts with one of a specific set of values.

Starting Values

Starting Values originally appeared on About.com Focus on JavaScript on Wednesday, November 18th, 2009 at 21:45:16.

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When to look at Libraries

Tue, 17 Nov 2009 09:41:26 +0000

Using JavaScript libraries may make writing your JavaScript easier.

Libraries provide you with a lot of common functionality that has already been written and tested by someone who probably knows JavaScript a lot better than you do. The problem is that if you jump into using libraries too quickly you end up never learning how to write JavaScript properly.

When to look at Libraries

When to look at Libraries originally appeared on About.com Focus on JavaScript on Tuesday, November 17th, 2009 at 09:41:26.

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JavaScript Link

Mon, 16 Nov 2009 07:45:01 +0000

There are good and bad ways to attach JavaScript to links in your page.

How do you attach your JavaScript into your page? In this short tutorial we start by looking at the really bad ways that some people who are new to JavaScript write their code and look at ways that we can progressively improve on the way we do it.

JavaScript Link

JavaScript Link originally appeared on About.com Focus on JavaScript on Monday, November 16th, 2009 at 07:45:01.

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Replacing Matches

Sun, 15 Nov 2009 16:38:43 +0000

Regular Expressions can be used to do a search and replace on your content.

You already know how useful the find and replace options are in your favourite editors. Being able to perform a find and replace within text strings in your JavaScript code can be equally useful and by using a regular expression you can even make the text that you are trying to find more generic (such as ignoring capitalisation and allowing for alternate spelling). The third tutorial on "regular expressions" shows you how to use the string.replace method to replace parts of a string that match a regular expression.

Replacing Matches

Replacing Matches originally appeared on About.com Focus on JavaScript on Sunday, November 15th, 2009 at 16:38:43.

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Referencing Form Fields

Sat, 14 Nov 2009 15:22:35 +0000

Form field names are used to pass the information to the server

The names that you give to the fields in your form in order for the server side processing to work may not be appropriate to use to references them from JavaScript. Fortunately JavaScript has an alternate way of being able to reference form fields.

Referencing Form Fields

Referencing Form Fields originally appeared on About.com Focus on JavaScript on Saturday, November 14th, 2009 at 15:22:35.

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Dynamic Forms

Fri, 13 Nov 2009 09:58:52 +0000

JavaScript can add complex HTML to a web page

A new addition to my library of scripts that you can use on your own site is my new Form object script which provides you with an object that has simple to use methods to create a form with all the form field types you are most likely to want to use (it doesn't handle file inputs or optgroups but most of the time you will not need those). The object uses standard DOM calls to add the form into your web page as well as providing plenty of ways to reference the fields from your stylesheet in order to format it the way you want.

Dynamic Forms

Dynamic Forms originally appeared on About.com Focus on JavaScript on Friday, November 13th, 2009 at 09:58:52.

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You Can't Protect Your Page Content

Thu, 12 Nov 2009 09:52:58 +0000

Web pages are open source and there is nothing you can do to protect the content

Every so often I receive emails about my Image Protection JavaScript that places the image in the background of a table with a transparent image in front of it. All of these emails have pointed out that there are other ways to obtain the image and that it is not really protected. In fact there is no way to stop people obtaining the content of your web page since they have it already on their computer when they view your page. The same is true even if you use JavaScript to encrypt your page source since your visitors all have something that can decrypt it for them (called a web browser). In fact applying something as simple as a no right click script (which is the least effective way to try to protect anything) will just drive visitors away from your site. Any of these techniques may stop newbie web users from taking your code and images (and will do so at least as effectively as much longer codes and more expensive solutions found elsewhere on the web) but nothing will prevent someone who knows how the web works from obtaining whatever they want from your site.

You Can't Protect Your Page Content originally appeared on About.com Focus on JavaScript on Thursday, November 12th, 2009 at 09:52:58.

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