How to use ajax to dynamically splice html code

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 += &#39;<span class="unchecked" name="category" checked="false" onclick="change(this);
    " value=&#39;+category.id+&#39; >&#39;+category.name+&#39;</span>&#39;+ &#39;<input type="hidden" id="category_id" name="category_id">&#39;;
}
//将html动态拼接到对应的p上面 $(&#39;.category-list&#39;).html(str);
}
, error:function (XMLHttpRequest, textStatus, errorThrown) {
    alert("请求失败！"+XMLHttpRequest+"==="+textStatus+"==="+errorThrown);
}
});
}