js中标签字符串的拼接

//1.用单双引号拼接
var valueDemo = "111";
var htmlStrs1 = '<option selected="selected" value="'+valueDemo+'"></option>';
alert(htmlStrs1);
//2.通过转义字符拼接
var htmlStrs2 = "<option selected="selected" value=""+valueDemo+"">"+valueDemo+"</option>";
alert(htmlStrs2);
//3.通过Jqquery直接创建标签对象
$("<option></option>")