User info finder block code by reusing Moodle Enrolment API

lms-dashboard.block.html

<div>
	<input type="text" id="fndr_student_finder_field" class="form-control" placeholder="Type User ID/Email/..." role="textbox" style="max-width: 15em; float: left; margin-right: 1em;" />
	<button id="fndr_student_finder_search" type="button" class="btn btn-primary" style="margin-right: 1em;">Search</button>
	<div id="fndr_student_finder_results" style="font-family: monospace; float: right;">Click Search button to display results</div>
</div>
<script type="text/javascript">
	// <![CDATA[
	var fndr_sesskey = document.querySelector('#page-header input[name=sesskey]').value;
	var fndr_endpoint = "/lib/ajax/service.php?sesskey=" + fndr_sesskey + "&info=core_enrol_get_potential_users";
	var fndr_search_template = '[{"index":0,"methodname":"core_enrol_get_potential_users","args":{"courseid":"___PROVIDE_YOUR_COURSEID___","enrolid":"___PROVIDE_YOUR_ENROLID___","search":"___SEARCHME___","searchanywhere":true,"page":0,"perpage":10}}]';

	document.getElementById("fndr_student_finder_search").addEventListener("click", function() {
		var fndr_search_keyword = document.getElementById("fndr_student_finder_field").value;

		if (fndr_search_keyword === "") {
			document.getElementById("fndr_student_finder_results").innerText = "You must provide a keyword to search!";
			return false;
		}

		var fndr_search_json = fndr_search_template.replace("___SEARCHME___", fndr_search_keyword);

		var xmlHttp = new XMLHttpRequest();
		xmlHttp.onreadystatechange = function() {
			if (xmlHttp.readyState == 4 && xmlHttp.status == 200) {
				var data = JSON.parse(xmlHttp.responseText);
				if (data[0].error === true) {
					alert("Error with response: " + JSON.stringify(data));
					return false;
				}
				var fndr_outputs = "";
				if (data[0].data.length > 0) {
					data[0].data.forEach(function(item, index) {
						fndr_outputs += "#" + index + ": ID#: " + item.idnumber + " Email: " + item.email + " Name: " + item.fullname + "<br>";
					});
				} else {
					fndr_outputs = "No results!";
				}

				document.getElementById("fndr_student_finder_results").innerHTML = fndr_outputs;
			}
		}
		xmlHttp.open("post", fndr_endpoint);
		xmlHttp.send(fndr_search_json);
	});
	// ]]>
</script>