Just a newbie asking about JS

UnderWing · 03-27-2003, 09:42 AM

I'm a complete newbie to Javascript, so here's my problem:

I'm making a calculator program (code following) that is simple and can only compute Addition, Subtraction, Multiplication, Division, and Powers. I use radio buttons to have the user input his/her type of equation, and two text fields to input the numbers involved. When they press a button, the page returns an alert window with the solution. I have gotten everything to work, except addition. It seems to want to treat the input as a string, instead of a variable. Here's the code:

<html>
<head>
<title>Untitled Document</title>
<meta http-equiv="Content-Type" content="text/html; charset=iso-8859-1">
</head>

<body bg="#ffffff" text="#000000">
<script language="JavaScript" type="text/javascript">
<!--
function solve()
{
var f = document.f;
var num1 = 0;
var num2 = 0;
var sign = 0;
var final = 0;
var i = 0;

/*check for num1.*/
num1 = f.num1.value;

/*check for sign.*/ /*signs: 1 = +, 2 = -, 3 = *, 4 = /, 5 = ^*/
for (i = 0; i < f.sign.length; i++) if (f.sign[i].checked) sign = i + 1;

/*check for num2.*/
num2 = f.num2.value;

if (sign == 1) final = (num1 + num2);
if (sign == 2) final = num1 - num2;
if (sign == 3) final = num1 * num2;
if (sign == 4) final = num1 / num2;
if (sign == 5) {
var power = num2;
final = num1;
while (power > 1) {
final = final * num1;
power--
}
}

alert(final);

}
</script>

<form name="f">
<input name="num1" value=0>
<br>
<input type="radio" name="sign" value="1"> +<br>
<input type="radio" name="sign" value="2"> -<br>
<input type="radio" name="sign" value="3"> *<br>
<input type="radio" name="sign" value="4"> /<br>
<input type="radio" name="sign" value="5"> ^<br>
<input name="num2" value=0>
<br>
<input type="button" value="Solve" onclick="solve(f);">
</form>
</body>
</html>

abc123 · 03-27-2003, 12:28 PM

to convert a string to an int:

Code:

var a_string = "123";
var the_int = parseInt(a_string);
alert(the_int * 10);
// should get 1230

saline · 03-27-2003, 01:23 PM

abc123 is right but I also just wanted to add one little thing. I copied your code into the program I use to edit javascript and guess what I found. final, the variable your using to hold the total, is technically a reserved word in javascript.

If you don't know what I mean by reserved word it's the keywords that the interpreter or compiler looks for like 'if' or 'for' or 'while'.

Strange thing is, final is reserved for future use, which means, at least right now, it doesn't do anything. So its ok to use but if someday someone uses your script on a browser where final is specified your script will crash and burn.

I would recommend using the variable name 'total' instead of final or maybe 'final_total' just to be super specific.

welcome to codenewbie!