var web = ['JavaScript', 'HTML', 'CSS'];
var parent = document.getElementById('test-list');
// 为了避免children的动态效果，所以先保存 parent.children;
var children = parent.children;
for(var i=0;i<children.length;++i) {
    if(web.map(function(x){return x.toUpperCase();}).indexOf(children[i].innerText.toUpperCase())===-1) {
         parent.removeChild(children[i]);
    }
}