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ColdFusion.getElementValue and $CF()

I first started doing Ajax programming using the Prototype framework.  As I learn the new CF8 Ajax features, I find myself looking for simple ways to replicate some of the functionality that is in prototype.  With prototype, you use $F('element') to return the value of a form field.  There is a similar method for CF8, but it needs a little tweak… 

The function that returns the value of a form element in ColdFusion 8's Ajax implementation is the following:


It's really handy because it will return a form field value for any type of form field – even select boxes and radio button. 

However, that's a lot of typing if you are using many form values in your JavaScript/Ajax code.  There is a super easy way to reduce this.  Make your own shorter function that just calls this.

 For example,

function $CF(element) {
        return ColdFusion.getElementValue(element);

 Here is an oversimplified example:

 <cfajaximport />
<cfform action="" method="post">
<cfinput type="text" name="testelement" VALUE="test" />
    function $CF(element) {
        return ColdFusion.getElementValue(element);

You could put the $CF function in a JS file that is used throughout your application.  But remember, you can only use ColdFusion.getElementValue() on pages that invoke the Ajax libraries.  In the example above, that's why I placed a <cfajaximport /> tag in there.  This example doesn't use Ajax, and including the libraries is really a waste of resources in this circumstance.  Save this trick for your true Ajax apps.  

More about ColdFusion.getElemenValue() from Adobe


4 Replies to “ColdFusion.getElementValue and $CF()”

  1. There is no built-in CF way to do this – as far as I know. However, you can use this function…

    function setElementValue(formElement, value)
    case ‘undefined’: return;
    case ‘radio’: formElement.checked = value; break;
    case ‘checkbox’: formElement.checked = value; break;
    case ‘select-one’: formElement.selectedIndex = value; break;

    case ‘select-multiple’:
    for(var x=0; x < formElement.length; x++) formElement[x].selected = value[x]; break; default: formElement.value = value; break; } }

  2. To me the benefit for us CFML developers is in the greater adoption (and the attendant increase in numbers of developers using the language) that Railo and OpenBD can bring to CFML as a language and community. For Adobe  http://rapid4me.com/?q=Adobe, I think the profit lies in Bolt (or whatever it will be called). Assuming a greater number of CF users (sites, developers, etc.), the need for a standard IDE increases (no knock on CFEclipse…I love and use it daily). I, personally, think this is where Adobe sees the dollars (see the opening of Flex as a server versus the incredible sales of Flex Builder since version 2 as a model).

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