current-dateTime() value is not updating on page-refresh event - xslt

Question

I set the value of an instance to current-dateTime(). I want to update this value on page-refresh event. So I have the following code:
<xf:action ev:event="page-refresh">
<xf:setvalue ref="instance('noCache')/val"><xsl:value-of select="current-dateTime()" /></xf:setvalue>
<!-- call to resource with new value-->
</xf:action>
This above code sets the instance value (dateTime) as the same which was at page-load !
Later I use this instance value to make GET request calls to a resource and pass this updated instance value as a parameter.
Note: Using current-dateTime() to pass a parameter to the resource to avoid using cached resources (since couldn't find a way to generate random numbers
Seems like the problem I feel is that the xsl variable current-dateTime() is evaluated only on page-load and the same value is used for page-refresh. Is there some other way I can get the updated dateTime on page-refresh event ?

Answer 1

With XSLTForms you can call Javascript functions on XPath expressions on client side, this way:
<xf:setvalue ref="instance('noCache')/val" value="getXMLDate()" ></xf:setvalue>
And write the getXMLDate() function in your HTML:
<script>
function gwtXMLDate(){
var d = new Date();
return d.toISOString();
}
</script>