Date Last Modified

Here's a script that tells visitors when the page they are looking at was last updated. It retrieves the Last Modified date from the properties of the HTML file and then displays it. This script is generally placed near the end of a page

<script language="JavaScript">
 <!-- 
 var LastUpdated = document.lastModified;
 document.writeln ("Page last updated " + LastUpdated);
 // -->
 </script>

Like the frame-breaker script, this works automatically without any kind of trigger code. Notice that the text "Page last updated" is written using JavaScript rather than plain HTML. The reason is that any browser that doesn't understand JavaScript, or has it turned off, will omit the entire line, rather than showing "Page last updated" with no date to follow.

If you use a script that will leave messy debris if the JavaScript can't be read, or is vital to the functioning of your page, then you need to use the <noscript> tag to explain to puzzled visitors why they're seeing a mess. For example:

<noscript>
This page requires JavaScript, which is not enabled on your browser.
</noscript>

This message will only be displayed on browsers that can't understand JavaScript. You can also include a regular hyperlink (<a href="alternativepage.htm">Alternative page</a>) within the noscript tags if you want to suggest a different page to your disappointed visitor. In fact any valid HTML code can be used between noscript tags.

You can place the noscript tags anywhere within the body of your page. You could put them at the top if the JavaScript is essential to the entire page, or put them in the position where the missing JavaScript is going to leave a gap.

One thing to bear in mind is that search engine spiders don't understand JavaScript, which means they do read the text within <noscript> tags. When the noscript is near the top of a page it can sometimes finish up as the main expression indexed by the search engine spiders, and you'll see it returned in search engine results.

Current Date

Here's a third simple script that comes as one piece. Wherever you place it on your page, it displays the current date (in the center of the page):

<SCRIPT LANGUAGE="JavaScript1.2">

<!-- This script and many more are available free online at -->
 <!-- The JavaScript Source! http://javascript.internet.com -->

<!-- Begin
 var months=new Array(13);
 months[1]="January";
 months[2]="February";
 months[3]="March";
 months[4]="April";
 months[5]="May";
 months[6]="June";
 months[7]="July";
 months[8]="August";
 months[9]="September";
 months[10]="October";
 months[11]="November";
 months[12]="December";
 var time=new Date();
 var lmonth=months[time.getMonth() + 1];
 var date=time.getDate();
 var year=time.getYear();
 if (year < 2000)    // Y2K Fix, Isaac Powell
 year = year + 1900; // http://onyx.idbsu.edu/~ipowell
 document.write("<center>" + lmonth + " ");
 document.write(date + ", " + year + "</center>");
 // End -->
 </SCRIPT>

This script takes up many lines and brings up an important issue in JavaScript - the sanctity of linebreaks. The most common error when copying and pasting scripts is losing linebreaks. If you get a script that doesn't work, the first thing you should check is that the linebreaks on your page are absolutely identical to the linebreaks in the original. Some lines may contain nothing more than a single bracket, but if you start combining these with other lines, thinking that it looks neater, you'll find your script won't work.

JavaScript for Non-Programmers
JavaScript for Non-Programmers
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