Calculators Effects >>> Leap Year.


		<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 
		checkYear(year)
		{
		

		return
		(((year
		%
		4
		==
		0)
		&&
		(year
		%
		100
		!=
		0))
		||
		(year
		%
		400
		==
		0))
		?
		1
		:
		0;

		}

		function 
		leap(form)
		{

		year 
		=
		form.year.value;

		var 
		Check1 =
		parseFloat(year);

		for
		(var 
		i =
		0; 
		i < 
		year.length; 
		i++)
		{

		var 
		sLetterCheck1 = 
		year.substring(i, 
		i+1);

		if
		(sLetterCheck1
		<
		"0"
		|| 
		sLetterCheck1 >
		"9")
		{

		alert("Enter 
		a valid year.");

		form.year.focus();

		form.year.select();

		return;

		   
		}

		}       

		if
		(year
		<
		1582)
		{

		form.result.value
		=
		"";

		alert("Year 
		must be greater than 1581.");

		form.year.focus();

		form.year.select();

		return;

		}

		checkYear(year);

		if
		(!checkYear(year))
		form.result.value
		=
		"not a leap year.";

		else
		form.result.value
		=
		"a leap year.";

		}

		function 
		MakeArray(n)
		{

		if
		(n
		<=
		0)
		{

		this.length
		=
		0;

		return
		this;

		}

		this.length
		= 
		n;

		for
		(var 
		i =
		1; 
		i <= 
		n; 
		i++)
		{

		this[i]
		=
		0;

		}

		return
		this;

		}

		var 
		listArray =
		new 
		MakeArray(160);

		var
		index
		=
		0;

		function 
		list(form)
		{

		startyear 
		=
		form.startyear.value;

		endyear 
		=
		form.endyear.value;

		var 
		Check1 =
		parseFloat(startyear);

		var 
		Check2 =
		parseFloat(endyear);

		for
		(var 
		i =
		0; 
		i < 
		startyear.length; 
		i++)
		{

		var 
		sLetterCheck1 = 
		startyear.substring(i, 
		i+1);

		if
		(sLetterCheck1
		<
		"0"
		|| 
		sLetterCheck1 >
		"9")
		{

		alert("Enter 
		a valid start year.");

		form.startyear.focus();

		form.startyear.select();

		return;

		   
		}

		}       

		for
		(var 
		i =
		0; 
		i < 
		endyear.length; 
		i++)
		{

		var 
		sLetterCheck2 = 
		endyear.substring(i, 
		i+1);

		if
		(sLetterCheck2
		<
		"0"
		|| 
		sLetterCheck2 >
		"9")
		{

		alert("Enter 
		a valid end year.");

		form.endyear.focus();

		form.endyear.select();

		return;

		   
		}

		}       

		if
		(startyear
		<
		1582)
		{

		form.yearlist.value
		=
		"";

		alert("Start 
		year must be greater than 1581.");

		form.startyear.focus();

		form.startyear.select();

		return;

		}

		else
		if
		(endyear
		<= 
		startyear)
		{

		form.yearlist.value
		=
		"";

		alert("End 
		year must be greater than start year.");

		form.endyear.focus();

		form.endyear.select();

		return;

		}

		else
		{

		index
		=
		0;

		for
		(var 
		i=startyear; 
		i <=endyear; 
		i++)
		{

		if
		(checkYear(i))
		{

		listArray[index]
		= 
		i;

		index++;

		      
		}

		   
		}

		}

		var 
		allYears;

		allYears 
		=
		"";

		for( 
		i =
		0; 
		i <
		index; 
		i++
		)
		{

		allYears 
		+= 
		listArray[i]
		+
		"\r"
		+
		"\n";

		form.yearlist.value
		= 
		allYears;

		   
		}

		}

		//  End -->

		</script>

		<form>

		Check For Leap Year:<br>

		Year:  
		<input 
		type=text
		name=year
		size=4> 
		is <input
		type=text
		name=result
		size=15>

		<br>

		<br>

		<input
		type=button
		value="Check 
		Year" 
		onClick="leap(this.form);">

		<br>

		Leap Years Within A Range:<br>

		Start Year:<input
		type=text
		name=startyear
		size=4><br>

		End year: 
		<input 
		type="text"
		name="endyear"
		size=4><br>

		<br>

		<input
		type=button
		name=listyears
		value="List 
		Years" 
		onClick="list(this.form);">

		<br>

		<textarea
		name=yearlist
		rows=10
		cols=11></textarea>

		</form>