Memory function for a calculator

**gaz545** · 12-01-2006, 10:27 AM

Right so im trying to make a memory function on a calculator, i want it to take the value in the input field and add it to a variable.

but i cant get it 2 do that

*compleate memory blank*

all i have managed to do, is get it to display the variable, and not add to it.

so far i have...

Code:

<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml">
<head>
<meta http-equiv="Content-Type" content="text/html; charset=ISO-8859-1" />
<title>Javascript Calculator</title>
<script language="JavaScript">
<!-- Begin

var memory = 0

function memoryshow(input) {
    input.value = memory
}

// if the number is 0, the new character will replace it, if it is not 0 then it will add it to the form.
function addChar(input, character) {
    if(input.value == null || input.value == "0")
        input.value = character
    else
        input.value += character
}

//Deletes the last digit in the form field.
function deleteChar(input) {
    input.value = input.value.substring(0, input.value.length - 1)
}

//Calculates the equation in the input field.
function compute(form)  {
    form.display.value = eval(form.display.value)
}

//Checks to see if the numbers/characters added into the input field are numbers or mathmatical symbals.
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 != ".") {
        alert("Invalid Entry!")
    return false
      }
    }
    }
    return true
}
// End -->
</script>
</head>

<body>
    <form>
        <input name="display" value="0" size="15">
        <br />
        <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=" 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=" 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=" 0 " onClick="addChar(this.form.display, '0')">
        <input type="button" value=" .  " onClick="addChar(this.form.display, '.')">
        
        <input type="button" value="=" name="enter" onClick="if (checkNum(this.form.display.value)) { compute(this.form) }">
        <input type="button" value=" + " onClick="addChar(this.form.display, '+')">
        <br />
        <br />
        <input type="button" value="Clear" onClick="this.form.display.value = 0 ">
        <input type="button" value="Delete" onClick="deleteChar(this.form.display)">
        <input type="button" value=" M " onclick="memoryshow(this.form.display)" />
    </form>
</body>
</html>

any help would be much appriciated.