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Trying to figure out why this SIMPLE math function will not work. If anyone can help me that would be great....Thanks

<!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=utf-8" />
<title>Calc Price</title>
<SCRIPT LANGUAGE="JavaScript">
function  doMath() {
var one = eval(document.theForm.elements[0].value)
var two = eval(document.theForm.elements[1].value)
var prod = one*two
var outp = "" 

}
  document.getElementById('outtab').innerHTML = outp 
} 
// End -->
</SCRIPT>
</head>
<body>
<div>
<form name="theForm">
<p>Please select:</p>
<select name="one">
  <option>1</option>
  <option>2</option>
  <option>3</option>
  <option>4</option>
  <option>5</option>
  <option>6</option>
  <option>7</option>
  <option>8</option>
  <option>9</option>
  <option>10</option>
</select>

<p>Price</p>
$<input name="two" DISABLED type="text" size="4" value="2.00">

<BR>Total:<SPAN ID="outtab"></SPAN>
<br>
<input type="button" onclick="doMath()" value="Calculate Total" >
</form>
</div>
</body>
</html>
2
Contributors
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5 Years
Discussion Span
Last Post by Airshow
0

i DIDNT add the full code, sorry...here is a revision to it...

<!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=utf-8" />
<title>Calc Price</title>
<SCRIPT LANGUAGE="JavaScript">
function  doMath() {
var one = eval(document.theForm.elements[0].value)
var two = eval(document.theForm.elements[1].value)
var outp = "" 
var prod = document.times.mult.value 
    ans = one*two
    outp =  ans 

}
  document.getElementById('outtab').innerHTML = outp 
} 
</SCRIPT>
</head>
<body>
<div>
<form name="theForm">
<p>Please select:</p>
<select name="one">
  <option>1</option>
  <option>2</option>
  <option>3</option>
  <option>4</option>
  <option>5</option>
  <option>6</option>
  <option>7</option>
  <option>8</option>
  <option>9</option>
  <option>10</option>
</select>

<p>Price</p>
$<input name="two" DISABLED type="text" size="4" value="2.00">

<BR><BR>Total:<SPAN ID="outtab"></SPAN>
<br><BR>
<input type="button" onclick="doMath()" value="Calculate Total" >
</form>
</div>
</body>
</html>
0

Revision again, I got it working:

<!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=utf-8" />
<title>Calc Price</title>
<SCRIPT LANGUAGE="JavaScript">
function  doMath() {
var one = eval(document.theForm.elements[0].value)
var two = eval(document.theForm.elements[1].value)
var outp = "" 
	{
    ans = one*two
    outp = " " + "$" + ans + ".00" + "/Month"

}
  document.getElementById('outtab').innerHTML = outp 
} 
</SCRIPT>
</head>
<body>
<div>
<form name="theForm">
<p>Please select:</p>
<select name="one">
  <option>1</option>
  <option>2</option>
  <option>3</option>
  <option>4</option>
  <option>5</option>
  <option>6</option>
  <option>7</option>
  <option>8</option>
  <option>9</option>
  <option>10</option>
</select>

<p>Price</p>
$<input name="two" DISABLED type="text" size="4" value="2.00">

<BR><BR>Total:<SPAN ID="outtab"></SPAN>
<br><BR>
<input type="button" onclick="doMath()" value="Calculate Total" >
</form>
</div>
</body>
</html>
0

Pat,

eval() :icon_eek:

It's part of javascript but seldom needs to be used; arguably never.

Number() returns a floating point conversion of its argument.

function doMath() {
  var one = Number(document.theForm.elements[0].value);
  var two = Number(document.theForm.elements[1].value);
  ans = one * two;
  outp = " " + "$" + ans.toFixed(2) + "/Month";
  document.getElementById('outtab').innerHTML = outp;
}

Remember to terminate each statement with a ; . Javascript does its best but may one day do something unexpected with unterminated statements. Proper termination also aids readability of the code.

Airshow

Edited by Airshow: n/a

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So now I want to do something a little different since i have a basic code there. I want to add a case switch to it. I want to price to change when they select certain one from the options...is there anyway of incorporating that?

<option selected="selected">5</option>
  <option>10</option>
  <option>15</option>
  <option>20</option>
  <option>30</option>
  <option>50</option>
  <option>100</option>
</select>

Like say:

case 1: document.write('2.00'); break;
case 2: document.write('1.00'); break;
case 3: document.write('0.75'); break;
case 4: document.write('0.50'); break;

and have it displayed in the

$<input name="two" DISABLED type="text" size="4" value="2.00">

Edited by patk570: n/a

0

oops, if 10 and 15 are selected case 1, if 20, case 2, if 30 is selected case 3 then the rest is case 4

0

What about something like this? Am I Close?

<!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=utf-8" />
<title>Calc Price</title>
<SCRIPT LANGUAGE="JavaScript">
function  doMath() {
var one = eval(document.theForm.elements[0].value);
var two = eval(document.theForm.elements[1].value);
var outp = "";
var outps = "";
	{
    ans = one*two;
    ansq = (one*two)*12;
    outp = " " + "$" + ans.toFixed(2) + "/Month";
    outps = " " + "$" + ansq.toFixed(2) + "/Year";

}
  document.getElementById('outtab').innerHTML = outp;
document.getElementById('outtab1').innerHTML = outps;
} 
</SCRIPT>
<script type="text/javascript">

function switchme(SNewSel) {

var sNewSel = document.getElementById("selection");
switch (sNewSel)
{
case "1": 
document.getElementById("price") = "2.00";
break;

case "2": 
document.getElementById("price") = "1.00"
break;

case "3": 
document.getElementById("price") = "0.75"
break;

case "4": 
document.getElementById("price") = "0.50"
break;

default: // unknown value -- do nothing
break;
}
}
</script>
</head>
<body>
<div>
<form name="theForm">
<p>Please select amount of GB:</p>
<select id="selection" name="one" onchange="switchme(this.value)">
  <option value="Choose">Please Choose</option>
  <option value="5">5</option>
  <option value="10">10</option>
  <option value="15">15</option>
  <option value="20">20</option>
  <option value="30">30</option>
  <option value="50">50</option>
  <option value="100">100</option>
</select>

<p>Price</p>
$<input id="price" name="two" DISABLED type="text" size="6" value="2.00">/GB

<BR><BR>Monthly Total:<SPAN ID="outtab"></SPAN>
<br>Yearly Total:<SPAN ID="outtab1"></SPAN>
<br><BR>
<input type="button" onclick="doMath()" value="Calculate Total" >
</form>
</div>
</body>
</html>
0

Pat,

Your code will simplify considerably by using the option values to store the unit prices.

function switchme(sel) {
  var value = sel[sel.selectedIndex].value;
  document.getElementById("price").innerHTML = value.toFixed(2);
}
<select id="selection" name="one" onchange="switchme(this)">
  <option value="Choose">Please Choose</option>
  <option value="2">5</option>
  <option value="1">10</option>
  <option value="0.75">15</option>
  <option value="0.5">20</option>
  <option value="0.45">30</option>
  <option value="0.4">50</option>
  <option value="0.34">100</option>
</select>

Airshow

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