CRM 2013 - Accessing innerHTML of a web resource.

Hi all,

I was wondering what is the best way to edit the string contents(inner html) of a web resources HTML in CRM 2013. We currently have the following code which we used (and worked) for 2011:

function ShowHelpText(fldName, txtLabel)
{
var newHTML = '<SPAN style='COLOR:green;BORDER-RIGHT-WIDTH: 0px; MARGIN: 0px; PADDING-LEFT: 0px; BORDER-TOP-WIDTH: 0px; BORDER-BOTTOM-WIDTH: 0px; BORDER-LEFT-WIDTH: 0px; PADDING-TOP: 0px' id='txt_' + fldName + '' ' +
'>' + txtLabel + '</SPAN>';
var z = Xrm.Page.getControl(fldName).getObject();
z.innerHTML = newHTML;
//Xrm.Page.ui.controls.get(fldName)._control.get_element().childNodes[1].innerHTML = newHTML;
Xrm.Page.getControl(fldName).setVisible(true);
}

The line "z.innerHTML" does not appear to work on its own, however I have had to comment out the bolded line in CRM2013 because I am getting an "error on load - undefined" error. Can anyone tell me what is the support way to change the innerHTML contents of a webresource on CRM2013 or what I may need to change in the above function so that I can pass in the field name and text label contents, then change the innerHTML of the field (web resource) to the txtLabel parameter successfully?

Thanks in advance