/**
 * Updates the options inside of a given HTML select tag from a SPARQL
 * result set delivered by a SPIN template call.
 * The template call must return the value as first column, and the
 * display label as second column.
 * @param id  the ID of the select element, e.g. "#mySelect")
 * @param template  the URI of the template to call
 * @param args  an object with the argument to the template call
 */
function updateSelect(id, template, args) {
	args['_template'] = template;
	args['ajax'] = true;
	$.getJSON("template", args, function(j) {
		var vars = j['head'].vars;
		var valueVar = vars[0];
		var labelVar = vars[1];
		var bindings = j['results'].bindings;
		var options = '';
	    for (var i = 0; i < bindings.length; i++) {
	    	var binding = bindings[i];
	        options += '<option value="' + binding[valueVar].value + '">' + binding[labelVar].value + '</option>';
	    }
	    $(id).html(options);
	});
}