javascript - 在 Javascript 中创建表格

Question

我有一个问题。我正在学习 javascript，但我不知道如何创建仅适用于 javascript 文件的表。我必须为每个字母频率输出创建一个表，但我不知道该怎么做。这是我应该拥有的输出:

一开始我想在 HTML 上工作，但我不能，因为那部分与测试相关，我的代码必须通过。在这里我将展示其中的一些:

display_letter_frequency(letter_frequency("Hello"),document.getElementById("frequency_table"));
    var rows = document.getElementById("frequency_table").querySelectorAll('tr')
    equal(rows.length, 4, "With input String 'Hello' there should be 4 table rows")
    equal(rows[0].querySelectorAll('td')[0].innerHTML, 'H', "1st td of 1st tr should have the value H");
    equal(rows[0].querySelectorAll('td')[1].innerHTML, '1', "2nd td of 1st tr should have the value 1");
    equal(rows[1].querySelectorAll('td')[0].innerHTML, 'E', "1st td of 2nd tr should have the value E");
    equal(rows[1].querySelectorAll('td')[1].innerHTML, '1', "2nd td of 2nd tr should have the value 1");
    equal(rows[2].querySelectorAll('td')[0].innerHTML, 'L', "1st td of 3rd tr should have the value L");
    equal(rows[2].querySelectorAll('td')[1].innerHTML, '2', "2nd td of 3rd tr should have the value 2");
    equal(rows[3].querySelectorAll('td')[0].innerHTML, 'O', "1st td of 4th tr should have the value O");
    equal(rows[3].querySelectorAll('td')[1].innerHTML, '1', "2nd td of 4th tr should have the value 1");

此外，我不能使用 console.log，只能编写将由测试人员回调的函数代码。这是我所做的，但我不知道它是否正确以及如何继续:

function display_letter_frequency(a,dom) {
if(a === undefined){
    return undefined
} else {
    var tbl     = document.createElement("table");
    var tblBody = document.createElement("tbody");
    for(var x in a){
        var row = document.createElement("tr");

        }
    }
}

此代码与我之前编写的函数有关，该函数在命令行中计算用户的频率字母:

function letter_frequency(s) {
if(s === undefined){
    return undefined
} else {
    var freq = {};
    for (var i = 0; i < s.length; i++) {
        var character = s.charAt(i).toUpperCase();
        if (freq[character]) {
            freq[character]++;
        } else {
            freq[character] = 1;
        }
    }
}
    return freq;
}

希望问题很清楚，你可以帮助我和需要它的人。我环顾了网络，他们讨论了一些频率表来定义我的问题。不知道对不对

Answer 1

尝试

for(var x in a){
        var row = document.createElement("tr");
        letterCell = document.createElement('td');
        freqCell = document.createElement('td');
        letterCell.innerHTML = x;
        freqCell.innerHTML = a[x];
        row.appendChild(letterCell);
        row.appendChild(freqCell);
        tblBody.appendChild(row);
    }
}

(未测试)