Simple calculation php
<p>hye guy,
Actually i'm still new in programming.
just wanna asking what wrong with this code?
i'm trying to make calculation inside a form.
Really appreciate if your guys can help.
Thank you.</p>

<pre><code>&lt;?php
$script = "
window.addEvent('domready', function() {
function calculate() {

var value1 = $('value1').value;
var value2 = $('value2').value;
var value3 = $('value3').value;
var value4 = $('value4').value;
var value5 = $('value5').value;


var total = ( value1 + value2 + value3 + value4 + value5);


// Check that the result is a finite number. If so, display the results.
if (!isNaN(monthly) &amp;&amp;
  (monthly != Number.POSITIVE_INFINITY) &amp;&amp;
  (monthly != Number.NEGATIVE_INFINITY)) {


  total.value = round(value1 +value2 +value3 +value4 + value5);

} else {
  // Otherwise, the user's input was probably invalid, so don't
  // display anything.

  total.value = '';

}
} 

// rounds number to two decimal places.
function round(x) {
return Math.round(x*100)/100;
}
$('compute').addEvent('click', calculate );
$('value1').addEvent('change', calculate );
$('value2').addEvent('change', calculate );
$('value3').addEvent('change', calculate );
$('value4').addEvent('change', calculate );
$('value5').addEvent('change', calculate );


 });
";
$doc =&amp; JFactory::getDocument();
$doc-&gt;addScriptDeclaration($script);
 ?&gt;
&lt;table&gt;
&lt;tr&gt;&lt;td colspan="3"&gt;&lt;b&gt;Enter Amount Information:&lt;/b&gt;&lt;/td&gt;&lt;/tr&gt;
&lt;tr&gt;
  &lt;td&gt;1)&lt;/td&gt;
  &lt;td&gt;Amount of the 1 :&lt;/td&gt;
  &lt;td&gt;&lt;input type="text" name="value1" id="value1" size="12" &gt;&lt;/td&gt;
 &lt;/tr&gt;

&lt;tr&gt;
  &lt;td&gt;2)&lt;/td&gt;
  &lt;td&gt;Amount of the 2 :&lt;/td&gt;
  &lt;td&gt;&lt;input type="text" name="value2" id="value2" size="12" &gt;&lt;/td&gt;
&lt;/tr&gt;

&lt;tr&gt;
  &lt;td&gt;3)&lt;/td&gt;
  &lt;td&gt;Amount of the 3 :&lt;/td&gt;
  &lt;td&gt;&lt;input type="text" name="value3" id="value3" size="12" &gt;&lt;/td&gt;
&lt;/tr&gt;

&lt;tr&gt;
  &lt;td&gt;4)&lt;/td&gt;
  &lt;td&gt;Amount of the 4 :&lt;/td&gt;
  &lt;td&gt;&lt;input type="text" name="value4" id="value4" size="12" &gt;&lt;/td&gt;
&lt;/tr&gt;
&lt;tr&gt;
  &lt;td&gt;5)&lt;/td&gt;
  &lt;td&gt;Amount of the 5 :&lt;/td&gt;
  &lt;td&gt;&lt;input type="text" name="value5" id="value5" size="12" &gt;&lt;/td&gt;
&lt;/tr&gt;

&lt;tr&gt;&lt;td colspan="3"&gt;
  &lt;input type="button" value="Compute" id='compute' " &gt;
&lt;/td&gt;&lt;/tr&gt;
&lt;tr&gt;&lt;td colspan="3"&gt;
  &lt;b&gt;Payment Information:&lt;/b&gt;
&lt;/td&gt;&lt;/tr&gt;


&lt;tr&gt;
  &lt;td&gt;5)&lt;/td&gt;
  &lt;td&gt;Your total will be:&lt;/td&gt;
  &lt;td&gt;&lt;input type="text" name="total" id="total" size="12" readonly='readonly'&gt;&lt;/td&gt;
&lt;/tr&gt;

&lt;/table&gt;
?&gt;
</code></pre>

<p>Regards,
ADik mat</p>
