i need help...how to add 2 number...javascript

**doctor javascript** · 11-15-2006, 09:27 AM

for example,

<html>
<head>
<script language="JavaScript">
function apple()
{
a=2;
b=2;
c=a+b;

document.write("The answer is ", c);

}
</script>
</head>
<body>
<h1> Calculate </h1>
<form name="form1">
<input type="button" value="Calculate" onClick="apple()">

</form>
</body>
</html>

The frustrating part is the answer is 22 instead of 4. Please help me. I am so frustrated!!!

**Twey** · 11-15-2006, 03:18 PM

Code:

<script language="JavaScript">

language is deprecated; type is required.

Code:

a=2;

You omitted the var keyword. If you intend to create globals, please create them in the global scope.

Code:

document.write("The answer is ", c);

You can't document.write() after the page has loaded without destroying the current page. Also, document.write() accepts only one argument.

Code:

  <script type="text/javascript">
    function apple() {
      var a = 2,
        b = 2,
        c = a + b;
      document.getElementById("apple_op").firstChild.nodeValue = "The answer is " + c;
      return false;
    }
  </script>
</head>
<body>
  <h1>Calculate</h1>
  <p id="apple_op"> </p>
  <form action="" onsubmit="return apple();">
    <input type="submit" value="Calculate">
  </form>
</body>

**mwinter** · 11-15-2006, 03:36 PM

Originally Posted by Twey

document.getElementById("apple_op").firstChild.nodeValue = "The answer is " + c;

...

<p id="apple_op"> </p>

You cannot assume that the text node will exist, and indeed in MSIE it does not, causing an error.

Mike

**Twey** · 11-15-2006, 04:05 PM

Oops, indeed so, my error.

Code:

  <script type="text/javascript">
    function apple() {
      var a = 2,
        b = 2,
        c = a + b,
        op = document.getElementById("apple_op");
      if(op.firstChild)
        op.firstChild.nodeValue = "The answer is " + c;
      else
        op.appendChild(document.createTextNode("The answer is " + c));
      return false;
    }
  </script>
</head>
<body>
  <h1>Calculate</h1>
  <p id="apple_op"> </p>
  <form action="" onsubmit="return apple();">
    <input type="submit" value="Calculate">
  </form>
</body>

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