如何利用ajax给html动态拼接代码

function get_all_category_with_id() {
 $.ajax( {
 type: "get", url: "../../../appUpload/getAllCategoryByid", async : false, dataType: "text", success: function (data) {
 var obj = JSON.parse(data);
 var str ="";
 //先将元素对应清空 $('.category-list').empty();
 for(var i = 0;
 i<obj.length;
 i++) {
 var category = obj[i];
 str += '<span class="unchecked" name="category" checked="false" onclick="change(this);
 " value='+category.id+' >'+category.name+'</span>'+ '<input type="hidden" id="category_id" name="category_id">';
}
//将html动态拼接到对应的p上面 $('.category-list').html(str);
}
, error:function (XMLHttpRequest, textStatus, errorThrown) {
 alert("请求失败！"+XMLHttpRequest+"==="+textStatus+"==="+errorThrown);
}
});
}