Hi. here is sample code.
You can see the comment marked as korean.
	var myCombo, myCombo2, myCombo3;
	function doOnLoad() {
		// from script
		myCombo = new dhtmlXCombo("combo_zone", null, null, "image");
		myCombo.setImagePath("../common/flags/");
		myCombo.enableFilteringMode(true);
		myCombo.setTemplate({input: "#capital#", option: "#capital# - #country#"});
		myCombo.addOption("1", {country: "Finland", capital: "Helsinki"}, null, "finland.png", true);
		myCombo.addOption("2", {country: "Germany", capital: "Berlin"}, null, "germany.png");
		myCombo.addOption("3", {country: "Great Britain", capital: "London"}, null, "britain.png");
		myCombo.addOption("4", {country: "Hungary", capital: "Budapest"}, null, "hungary.png");
		// from JSON
		myCombo2 = new dhtmlXCombo("combo_zone2", null, null, "image");
		myCombo2.setImagePath("../common/flags2/");
		myCombo2.setDefaultImage("flag_green.png");
		myCombo2.enableFilteringMode(true);
		myCombo2.load("../common/data_consoles.json");
		// from XML
		myCombo3 = new dhtmlXCombo("combo_zone3", null, null, "image");
		myCombo3.setImagePath("../common/flags2/");
		myCombo3.setDefaultImage("flag_blue.png");
		myCombo3.enableFilteringMode(true);
		myCombo3.load("../common/data_os.xml");
		// https://dhtmlx.com/docs/products/dhtmlxCombo/samples/03_text_templates/01_text_templates.html
		// Add
		// from script - korean			
		myCombo = new dhtmlXCombo("combo_zone_korean", null, null, "image");
		myCombo.setImagePath("../common/flags/");
		myCombo.enableFilteringMode(true);
		myCombo.setTemplate({input: "#capital#", option: "#capital# - #country#"});
		myCombo.addOption("1", {country: "가나다", capital: "가나다"}, null, "finland.png", true);
		myCombo.addOption("2", {country: "가바차", capital: "가바차"}, null, "germany.png");
		myCombo.addOption("3", {country: "가카하", capital: "가카하"}, null, "britain.png");
	}