I had some issues setting this up, found out the joomla cms we used doesnt accept jquery, here is the javascript code to add hiddenfields needed by eloqua to integrate external forms:
<script>
function addHidden() {
var div= document.createElement('div');
div.innerHTML= '<input type="hidden" name="elqFormName" value="contact-us-full"><input type="hidden" name="elqSiteID" value="23693100">';
document.getElementById("ContactUs").appendChild(div);
}
</script>
html
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add this to the submit button
onclick="addHidden();"