JavaScript: Calculator Script - Leap Year Calculator

Main Calculator Script Leap Year Calculator

<!-- TWO STEPS TO INSTALL LEAP YEAR CALCULATOR:

1.  Copy this part of code inside your HTML HEAD

2.  Add the last code into the BODY of your HTML document  -->

<HEAD><title>JavaScript, java script, javascripts, script, javascript free code!</title>

<!-- 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>

</HEAD>

<BODY>

<form>

Check For Leap Year:<br>

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

<br>

<p>

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>

<br>

Click Here if you need help to install the JavaScript

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