IFE-31 笔记

//城市判断
function  cityCheck(){
    var data = {
        bj:[‘北京大学‘,‘清华大学‘,‘北京外语‘],
        sc:[‘四川大学‘,‘电子科技大学‘,‘西南交大‘]
    };
    var cityVal = choose_city.options[choose_city.selectedIndex].value;
    choose_school.innerHTML = ‘‘;
    for(var i = 0; i < data[cityVal].length; i ++){
        //添加过个innHTML记得为 innHTML +=
        choose_school.innerHTML  += ‘<option>‘ + data[cityVal][i] + ‘</option>‘;
        console.log(data[cityVal][i])
        console.log(i)
    }