var list = document.getElementById('test-list');

for (var i = 0; i < list.children.length;) {

       // if (["JavaScript", "HTML", "CSS"].indexOf(list.children[i].innerText) == -1) {

        if (!["JAVASCRIPT", "HTML", "CSS"].includes(list.children[i].innerText.toUpperCase())) {

            list.removeChild(list.children[i]);

        } else {

            i++; //只有web有关的节点才++;

        }

    }