Dream.In.Code > Random number within a given range

no2pencil

6 May, 2008 - 07:04 PM

Random number within a given range

Here are the steps in order to generate random numbers from a given range.
1st, we get a return value from the random() function. This value will be between 0.0 & 1.0.
We then multiply this value with the difference of the maximum value, & one less than the minumum value in our given range.
After that, we use the floor() function, to convert it into an integer.
Lastly, add the minimum value of our given range, to the number we came up with from above.

CODE

<html>
<head>
<title>JavaScript Random Numbers</title>
</head>
<body>
<script language=JavaScript>

</script>
</body></html>

The code above generates a random number between 5 and 10. With 5 being our minimum, & 10 being our maximum.

Random number within an array

CODE

<html>
<head>
<title>JavaScript Random Numbers</title>
</head>
<body>
<script language="JavaScript">

</script>
</body></html>

The code example above generates a random number between 1 and 9. Again, with 1 being our minimum, & 9 being our maximum.

mocker

7 May, 2008 - 09:35 AM

Just to add to your last example.. if you want to get a random element of the array, it usually is not a good idea to hardcode how many elements are in that array. I use the following code to get a random element of an array links[] and write it to a div

CODE

function newLink(){
var lmax = links.length;
var random_num = (Math.floor((Math.random()*lmax)+1));
var d = document.getElementById('rlink');
var newhtml = "<a href='"+links[random_num]+"'>"+links[random_num]+"</a>";
d.innerHTML = newhtml;
};