How to manipulate a text input as a number for calculation?

Hi,

I am not sure how to take a text input and convert it into a number and do calculation on it. I have searched but I could not find any workable sample that meets my situation. Anyone have any samples or suggestions would be greatly appreciated.

I have included a section of code. Looking at the code, you will probably see that I am fairly new at CF and web development

The text input field is "size" and I have a validation check on size using the function validatSize. No matter what I enter for size, 0.9 or 1.3, the validation always returns the "Please enter a size (cm)" message. I can not get out of this mode to continue programming (basically I am stuck) Thanks.

Here is the cold fusion method:

<cfif not IsDefined("size")><cfset size = "0"></cfif>

<script language="JavaScript"><!--

function validateSize(form) {
  if ((document.breast5.size > 0)) {
    return true;
  } else {
    alert("Please enter a size (cm)");
    return false;
  }
}

// --></script>

<cfset diseasesite = "#site#">
<cfinclude template=stdheader.cfm>

<tr>
	<td colspan=2 bgcolor=ffFFff height=300 valign=top>&nbsp;</td>
	<td colspan=2 bgcolor=ffFFff>
	<cfoutput>
	<font size=2 face="Arial, Helvetica">
	<b>What is the size of tumor:</b>
			<P>
			<form name="breast5" method="post" action="breast5.cfm" onSubmit="return validateSize(this)">
			<input type="text" name="size" value="#size#"> cm
			<input type="hidden" name="site" value="#site#">
			<input type="hidden" name="type" value="#type#">
			<input type="hidden" name="m" value="#m#">
			<input type="hidden" name="n" value="#n#">
			<input type="hidden" name="t" value="Unknown">
			<table>
			<tr><td></td></tr>
			<tr>
			<td align=left></td>
			<td>
			<input type="submit" value="Continue ...">
			</td>
			</tr>
			</table>
			</form>		
	</font>
	</cfoutput>
	</td>
	<td bgcolor=ffFFff>&nbsp;</td>
</tr>

<cfinclude template=stdfooter.cfm>

Code (markup):

 

this is more of a javascript problem than a coldfusion problem..


the problem is that document.breast5.size is an input object..
document.breast5.size.value will return the value inside that input object


use alerts() to do testing..

i.e.

function validateSize(form) {
  alert("document.breast5.size =" + document.breast5.size);
  alert("document.breast5.size.value =" + document.breast5.size.value);
  if ((document.breast5.size > 0)) {
    alert("returning true 1");
    return true;
  } else {
    if ((document.breast5.size.value > 0)) {
      alert("returning true 2");
      return true;
    }
    alert("Please enter a size (cm)");
    return false;
  }
}

Code (markup):

size also sounds like it could be a keyword.. i'm not entirely sure if that could cause a problem

 

Thanks Jamie, the alert really helps (at least it helps get me going again )

kudos!

What is the best way to check and make sure the user enter a number and not a char?

 

For javascript you could use the isNaN function

http://www.w3schools.com/jsref/jsref_isNaN.asp

Another option is to use a CFFORM/CFINPUT and use validate="float" or validate="integer".

http://livedocs.adobe.com/coldfusion/6.1/htmldocs/tags-p65.htm

But don't rely on just javascript. Re-check the value is numeric when the form is submitted.

 

Thank you so much, these are great references...