Displaying random text on a web page using JavaScript - 2

Now that you know how to randomly display text, we'll see how we can display this text as a marquee (using the <marquee> tag) in Internet Explorer or make this text blink (using the <blink> tag in Netscape Communicator).

The first step is to make a browser detection script. Depending on the browser, we execute the appropriate document.write() method.

The browser detention script use the appName property of the navigator object.

<script language="JavaScript">
<!--

var r_text = new Array ();
r_text[0] = "All the leaves are brown";
r_text[1] = "And the sky is grey";
r_text[2] = "I've been for a walk";
r_text[3] = "On a winter's day";
r_text[4] = "I'd be safe and warm";
r_text[5] = "If I was in L.A.";
r_text[6] = "California dreaming, On such a winter's day";

var i = Math.round(6*Math.random());

if (navigator.appName == "Netscape")
   {
   document.write("<blink><font color='
   #FF0000'>" + r_text[i] + "</font></blink>");
   }
else
   {
   document.write("<marquee><font color='#FF0000'>" +
   r_text[i] + "</font></marquee>");
   }

//-->
</script>

We first put all the text strings as individual array elements. Remember, JavaScript arrays are zero indexed - the first element of an array in JavaScript has an index of 0. Our array r_text consists of seven elements. We, thus, need a random number between 0 and 6.
The Math.random() method returns a floating point (decimal) number between 0.0 and 1.0. We multiply this with 7 to get numbers between 0.0 and 7.0 but that would still contain decimals. To get an integer we use the JavaScript Math.floor() method. This integer is then used as an index to retrieve the string from the r_text array.

The Result
Click on the refresh button to see another text string below.