Dynamically add text box

function test(){
    num+=1;
	var htmlCont="";
	htmlCont += "<div class='till'> " 
		  +"<div class='form-row'><div class='col-3 text-center'> <p></p></div>"
		  +" <div class='col-6'>"
		  +"		            <div class='form-group form-row'>"
		  +"	                <label for='' class='col-3 text-right sr-only'>测试</label>"
		  +"	                <input type='text' class='form-control col-7' id='tt' name='tt' placeholder='测试'>"
		  +"	                <span class='col-2 small_area'></span>"
		  +"		            </div>"
		  +"		        </div>"
		  +"	    </div>"
		  +"	</div>";
		 // var obj=document.getElementById("addHtml").innerHTML;
		 // document.getElementById("addHtml").innerHTML=obj+htmlCont;
	$("#addHtml").append(htmlCont);

}

Record another usage:

$("#test").find("tbody").find("tr:eq("+i+")").find("td:eq(7)").find("input:eq(0)").prop('checked',true);