Calculators Effects >>> Prime Number.


		<script 
		language="javascript"
		type="text/javascript">

		/* Visit http://www.yaldex.com/ 
		for full source code

		and get more free JavaScript, CSS and DHTML scripts! */

		<!-- Begin

		function 
		calculate(form)
		{

		var 
		num=parseInt(form.number.value);

		if
		(isNaN(num)
		|| 
		num <
		0)
		{

		form.result.value=(form.number.value
		+
		" is not a valid number!  Try 
		again!");

		}

		if
		(num
		==
		1
		|| 
		num ==
		2)
		{

		form.result.value=(num
		+
		" is prime!");

		}

		for
		(var 
		i=2;i<num;i++)
		{

		if
		(num
		% 
		i ==
		0)
		{

		var 
		prime="yes";

		form.result.value=(num
		+
		" is not prime.  It is divisible 
		by " 
		+ 
		i +
		".");

		break;

		}

		if
		(num
		% 
		i !=
		0)
		var 
		prime="no";

		}

		if
		(prime
		==
		"no")
		form.result.value=(num
		+
		" is prime!");

		} 

		// End -->

		</SCRIPT>

		<form
		name=form>

		<h2>Prime 
		Number Calculator</h2>

		Please enter a number:<br>

		<input
		type=text
		name=number
		size=7>

		<input 
		type="button"
		value="Calculate"
		onClick="calculate(this.form)">

		<br><br>

		<input
		type=text
		name=result
		size=45
		value="">

		</form>
Prime Number Calculator
