<HTML>
<HEAD>
<!--
JavaScript Calculator
Terrence Ma
Modified from JavaScript.com (http://javascript.internet.com/calculators/)
07/16/2000
-->

<TITLE>JavaScript Calculator</TITLE>

<style type="text/css">
<!--
p {font-size: 12pt}
.red {color: red}
.blue {color: blue}
-->
</style>

<SCRIPT LANGUAGE="JavaScript">
<!-- Original: Steve Dulaney -->
<!-- Web Site: http://www.hmhd.com/steve -->

<!-- This script and many more are available free online at -->
<!-- The JavaScript Source!! http://javascript.internet.com -->

<!-- Begin
var Memory = 0;
var Number1 = "";
var Number2 = "";
var NewNumber = "blank";
var opvalue = "";

function Display(displaynumber) {
document.calculator.answer.value = displaynumber;
}

function MemoryClear() {
Memory = 0;
document.calculator.mem.value = "";
}

function MemoryRecall(answer) {
if(NewNumber != "blank") {
Number2 += answer;
} else {
Number1 = answer;
}
NewNumber = "blank";
Display(answer);
}

function MemorySubtract(answer) {
Memory = Memory - eval(answer);
}

function MemoryAdd(answer) {
Memory = Memory + eval(answer);
document.calculator.mem.value = " M ";
NewNumber = "blank";
}

function ClearCalc() {
Number1 = "";
Number2 = "";
NewNumber = "blank";
Display("");
}

function Backspace(answer) {
answerlength = answer.length;
answer = answer.substring(0, answerlength - 1);
if (Number2 != "") {
Number2 = answer.toString();
Display(Number2);
} else {
Number1 = answer.toString();
Display(Number1);
}
}

function CECalc() {
Number2 = "";
NewNumber = "yes";
Display("");
}

function CheckNumber(answer) {
if(answer == ".") {
Number = document.calculator.answer.value;
if(Number.indexOf(".") != -1) {
answer = "";
}
}
if(NewNumber == "yes") {
Number2 += answer;
Display(Number2);
}
else {
if(NewNumber == "blank") {
Number1 = answer;
Number2 = "";
NewNumber = "no";
}
else {
Number1 += answer;
}
Display(Number1);
}
}
function AddButton(x) {
if(x == 1) EqualButton();
if(Number2 != "") {
Number1 = parseFloat(Number1) + parseFloat(Number2);
}
NewNumber = "yes";
opvalue = '+';
Display(Number1);
}
function SubButton(x) {
if(x == 1) EqualButton();
if(Number2 != "") {
Number1 = parseFloat(Number1) - parseFloat(Number2);
}
NewNumber = "yes";
opvalue = '-';
Display(Number1);
}
function MultButton(x) {
if(x == 1) EqualButton();
if(Number2 != "") {
Number1 = parseFloat(Number1) * parseFloat(Number2);
}
NewNumber = "yes";
opvalue = '*';
Display(Number1);
}
function DivButton(x) {
if(x == 1) EqualButton();
if(Number2 != "") {
Number1 = parseFloat(Number1) / parseFloat(Number2);
}
NewNumber = "yes";
opvalue = '/';
Display(Number1);
}
function SqrtButton() {
Number1 = Math.sqrt(Number1);
NewNumber = "blank";
Display(Number1);
}
function PercentButton() {
if(NewNumber != "blank") {
Number2 *= .01;
NewNumber = "blank";
Display(Number2);
}
}
function RecipButton() {
Number1 = 1/Number1;
NewNumber = "blank";
Display(Number1);
}
function NegateButton() {
Number1 = parseFloat(-Number1);
NewNumber = "no";
Display(Number1);
}
function EqualButton() {
if(opvalue == '+') AddButton(0);
if(opvalue == '-') SubButton(0);
if(opvalue == '*') MultButton(0);
if(opvalue == '/') DivButton(0);
Number2 = "";
opvalue = "";
}
// End -->
</script>

<NOSCRIPT>
Your browser does not support JavaScript, or JavaScript is not enabled. Sorry !<BR>
</NOSCRIPT>

</HEAD>

<BODY>

<CENTER><H2>JavaScript Calculator</H2></CENTER>
<HR>

<center>
<form name="calculator">
<table bgcolor="#aaaaaa" width=220>
<tr><td>
<table bgcolor="#cccccc" border=1>
<tr><td>
<table border=0 cellpadding=0>
<tr><td bgcolor="#000080"><b style="color:white">JavaScript Calculator</b></td></tr>
<tr><td>
<table width="100%" border=0>
<tr><td colspan=6><input type="text" name="answer" size=30 maxlength=30 onChange="CheckNumber(this.value)"></td></tr>
<tr><td colspan=6>
<table border=0 cellpadding=0>
<tr><td>
<input type="text" name="mem" size=3 maxlength=3> <input type="button" name="backspace" class="red" value="Backspace" onClick="Backspace(document.calculator.answer.value); return false;"> <input type="button" name="CE" class="red" value=" CE " onClick="CECalc(); return false;"> <input type="reset" name="C" class="red" value=" C " onClick="ClearCalc(); return false;">
</td></tr>
</table>
</td></tr>
<tr><td><input type="button" name="MC" class="red" value=" MC " onClick="MemoryClear(); return false;"></td>
<td><input type="button" name="calc7" class="blue" value=" 7 " onClick="CheckNumber('7'); return false;"></td>
<td><input type="button" name="calc8" class="blue" value=" 8 " onClick="CheckNumber('8'); return false;"></td>
<td><input type="button" name="calc9" class="blue" value=" 9 " onClick="CheckNumber('9'); return false;"></td>
<td><input type="button" name="divide" class="red" value=" / " onClick="DivButton(1); return false;"></td>
<td><input type="button" name="sqrt" class="blue" value="sqrt" onClick="SqrtButton(); return false;"></td></tr>
<tr><td><input type="button" name="MR" class="red" value=" MR " onClick="MemoryRecall(Memory); return false;"></td>
<td><input type="button" name="calc4" class="blue" value=" 4 " onClick="CheckNumber('4'); return false;"></td>
<td><input type="button" name="calc5" class="blue" value=" 5 " onClick="CheckNumber('5'); return false;"></td>
<td><input type="button" name="calc6" class="blue" value=" 6 " onClick="CheckNumber('6'); return false;"></td>
<td><input type="button" name="multiply" class="red" value=" * " onClick="MultButton(1); return false;"></td>
<td><input type="button" name="percent" class="blue" value=" % " onClick="PercentButton(); return false;"></td></tr>
<tr><td><input type="button" name="MS" class="red" value=" MS " onClick="MemorySubtract(document.calculator.answer.value); return false;"></td>
<td><input type="button" name="calc1" class="blue" value=" 1 " onClick="CheckNumber('1'); return false;"></td>
<td><input type="button" name="calc2" class="blue" value=" 2 " onClick="CheckNumber('2'); return false;"></td>
<td><input type="button" name="calc3" class="blue" value=" 3 " onClick="CheckNumber('3'); return false;"></td>
<td><input type="button" name="minus" class="red" value=" - " onClick="SubButton(1); return false;"></td>
<td><input type="button" name="recip" class="blue" value="1/x " onClick="RecipButton(); return false;"></td></tr>
<tr><td><input type="button" name="Mplus" class="red" value=" M+ " onClick="MemoryAdd(document.calculator.answer.value); return false;"></td>
<td><input type="button" name="calc0" class="blue" value=" 0 " onClick="CheckNumber('0'); return false;"></td>
<td><input type="button" name="negate" class="blue" value="+/- " onClick="NegateButton(); return false;"></td>
<td><input type="button" name="dot" class="blue" value=" . " onClick="CheckNumber('.'); return false;"></td>
<td><input type="button" name="plus" class="red" value=" + " onClick="AddButton(1); return false;"></td>
<td><input type="button" name="equal" class="red" value=" = " onClick="EqualButton(); return false;"></td>
</tr>
</table>
</td></tr>
</table>
</td></tr>
</table>
</td></tr>
</table>
</form>
</center>

<HR>
<A HREF="http://www.terrence.com/jscript/calculator.html.txt">Program Source</A>
<BR>

</BODY>
</HTML>