Javascript 如何将下拉列表中的值推送到数组中，并将数组添加到表中？

这是JavaScript。select的id为“Countries”

该表将插入一个名为“up\u bottom”的div中

试试这个

function addTeams(){
    var leagueArray = [];
    var county=document.getElementById("counties");
    for (i = 0; i < county.options.length; i++) {
       leagueArray[i] = county.options[i].value;
    }
    display(leagueArray);
}

function display(leagueArray) {
    var table = document.createElement("table");
    for (var i=0; i<leagueArray.length; i++) {
        var row = table.insertRow();
        for (var j=0; j<leagueArray[i].length; j++) {
            var cell = row.insertCell();
            cell.appendChild(document.createTextNode(leagueArray[i]));
        }
    }
    var tableDiv = document.getElementById("up_bottom");
    tableDiv.appendChild(table);
}

addTeams();

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请执行以下步骤

从下拉列表中获取选定值 将所选值放入数组中 创建一个tr元素的字符串，并在第一个tr元素之前将其追加到表中

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和控制台中是否有错误？出现了什么问题？未捕获的TypeError:无法读取null的属性'appendChild'

function addTeams(){
    var leagueArray = [];
    var county=document.getElementById("counties");
    for (i = 0; i < county.options.length; i++) {
       leagueArray[i] = county.options[i].value;
    }
    display(leagueArray);
}

function display(leagueArray) {
    var table = document.createElement("table");
    for (var i=0; i<leagueArray.length; i++) {
        var row = table.insertRow();
        for (var j=0; j<leagueArray[i].length; j++) {
            var cell = row.insertCell();
            cell.appendChild(document.createTextNode(leagueArray[i]));
        }
    }
    var tableDiv = document.getElementById("up_bottom");
    tableDiv.appendChild(table);
}

addTeams();