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Scientific Calculator

JavaScript calculator that does many advanced functions - cosine, sine, tangent, square root, exponents, etc.

Sample:

Insert this code before </head>

<SCRIPT LANGUAGE="JavaScript">



<!-- Begin
function addChar(input, character) {
if(input.value == null || input.value == "0")
input.value = character
else
input.value += character
}
function cos(form) {
form.display.value = Math.cos(form.display.value);}
function sin(form) {
form.display.value = Math.sin(form.display.value);}
function tan(form) {
form.display.value = Math.tan(form.display.value);}
function sqrt(form) {
form.display.value = Math.sqrt(form.display.value);}
function ln(form) {
form.display.value = Math.log(form.display.value);}
function exp(form) {
form.display.value = Math.exp(form.display.value);}
function sqrt(form) {
form.display.value = Math.sqrt(form.display.value);}
function deleteChar(input) {
input.value = input.value.substring(0, input.value.length - 1)
}
function changeSign(input) {
if(input.value.substring(0, 1) == "-")
input.value = input.value.substring(1, input.value.length)
else
input.value = "-" + input.value
}
function compute(form)  {
form.display.value = eval(form.display.value)}
function square(form)  {
form.display.value = eval(form.display.value) *
eval(form.display.value)}
function checkNum(str)  {
for (var i = 0; i < str.length; i++) {
var ch = str.substring(i, i+1)
if (ch < "0" || ch > "9") {
if (ch != "/" && ch != "*" && ch != "+" && ch !=
"-" && ch != "."
&& ch != "(" && ch!= ")") {
alert("invalid entry!")
return false
         }
      }
   }
return true
}
// End -->
</SCRIPT>

Insert this code before </body>

<form>
<input name="display" value="0" size=25>
    <br>
<input type="button" value="   exp  " onClick="if (checkNum(this.form.display.value))
{ exp(this.form) }">
<input type="button" value="    7    " onClick="addChar(this.form.display, '7')">
<input type="button" value="    8    " onClick="addChar(this.form.display, '8')">
<input type="button" value="    9    " onClick="addChar(this.form.display, '9')">
<input type="button" value="    /    " onClick="addChar(this.form.display, '/')">
<br>
<input type="button" value="    ln    " onClick="if (checkNum(this.form.display.value))
{ ln(this.form) }">
<input type="button" value="    4    " onClick="addChar(this.form.display, '4')">
<input type="button" value="    5    " onClick="addChar(this.form.display, '5')">
<input type="button" value="    6    " onClick="addChar(this.form.display, '6')">
<input type="button" value="    *    " onClick="addChar(this.form.display, '*')">
<br>
<input type="button" value="   sqrt  " onClick="if (checkNum(this.form.display.value))
{ sqrt(this.form) }">
<input type="button" value="    1    " onClick="addChar(this.form.display, '1')">
<input type="button" value="    2    " onClick="addChar(this.form.display, '2')">
<input type="button" value="    3    " onClick="addChar(this.form.display, '3')">
<input type="button" value="    -    " onClick="addChar(this.form.display, '-')">
<br>
<input type="button" value="    sq   " onClick="if (checkNum(this.form.display.value))
{ square(this.form) }">
<input type="button" value="   0     " onClick="addChar(this.form.display, '0')">
<input type="button" value="    .    " onClick="addChar(this.form.display, '.')">
<input type="button" value="   +/-   " onClick="changeSign(this.form.display)">
<input type="button" value="    +    " onClick="addChar(this.form.display, '+')">
<br>
<input type="button" value="    (    " onClick="addChar(this.form.display, '(')">
<input type="button" value="   cos   " onClick="if (checkNum(this.form.display.value))
{ cos(this.form) }">
<input type="button" value="   sin   " onClick="if (checkNum(this.form.display.value))
{ sin(this.form) }">
<input type="button" value="   tan   " onClick="if (checkNum(this.form.display.value))
{ tan(this.form) }">
<input type="button" value="    )    " onClick="addChar(this.form.display, ')')">
<br>
<input type="button" value="  Clear  " onClick="this.form.display.value = 0 ">
<input type="button" value=" Back Space  " onClick="deleteChar(this.form.display)">
<input type="button" value="   Enter    " name="enter" onClick="if (checkNum(this.form.display.value))
{ compute(this.form) }">
</FORM>

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