You can use <table> for that to structure your text:
let numbers = "<tbody>";
for (let i = 1; i <= 13; i++){
numbers += '</tr>';
for (let j = 1; j<= 13; j++){
numbers += `<td>${i*j}</td>`;
}
numbers += '</tr>';
}
numbers += "</tbody>"
const element = document.querySelector("#element");
element.innerHTML = numbers;
td {
text-align: right;
width: 2em;
}
<table id="element">
You could be ambitious and, like David said, use CSS to take the weight of how the data is meant to be displayed. I've used CSS grid in this example which means you only need to have one loop, and the CSS takes care of the rest.
const arr = [];
const size = 13;
const limit = size * size;
// Push an HTML template string into
// the array
for (var i = 1; i <= limit; i++) {
arr.push(`<div>${i}</div>`);
}
// Add the joined array (it makes an HTML string
// to the element with the `grid` class
const grid = document.querySelector('.grid');
grid.innerHTML = arr.join('');
.grid {
display: grid;
grid-template-columns: repeat(13, 30px);
grid-gap: 0.2em;
}
.grid div {
border: 1px solid #cdcdcd;
font-size: 0.8em;
background-color: #efefef;
text-align: center;
padding: 0.5em 0;
}
<div class="grid"></div>
Additional documentation
Edit: you can even create a function that will accept a number, and, using CSS variables, the function will work out the size of the grid required and return the HTML.
function createGrid(columns) {
const arr = [];
const grid = columns * columns;
document.documentElement.style.setProperty('--columns', columns)
// Push an HTML template string into
// the array
for (var i = 1; i <= grid; i++) {
arr.push(`<div>${i}</div>`);
}
return arr.join('');
}
const grid = document.querySelector('.grid');
grid.innerHTML = createGrid(5);
:root {
--columns: 13;
}
.grid {
display: grid;
grid-template-columns: repeat(var(--columns), 40px);
grid-gap: 0.2em;
}
.grid div {
border: 1px solid #cdcdcd;
font-size: 0.8em;
background-color: #efefef;
text-align: center;
padding: 0.5em 0;
}
<div class="grid"></div>
You can use grid approach with some CSS variables to make cell elements, for more details see comments in Code snippet:
Also you could render headings of the cells.
const gridSize = 13;
// get grid element
const grid = document.querySelector('.grid');
// create temporary wrapper
const fragmentWrapper = document.createDocumentFragment();
const renderTop = () => {
for (var i = 0; i <= gridSize; i++) {
if (i === 0) {
// render mult char
renderCell('x');
continue;
}
renderCell(i, true);
}
}
const renderGrid = () => {
// append cells to wrapper
for (var i = 1; i <= gridSize; i++) {
for (var j = 0; j <= gridSize; j++) {
if (j === 0) {
// render heading cell
const num = i;
renderCell(num, true);
continue;
}
// render default cell
const num = i * j;
renderCell(num);
}
}
}
const renderCell = (num, select = false) => {
// create temporary cell
const cell = document.createElement('div');
cell.className = 'cell';
// if requested to highligh cell
select && cell.classList.add('select');
cell.innerText = `${ num }`;
// add cell to grid
fragmentWrapper.append(cell);
}
renderTop();
renderGrid();
// set grid size
grid.style.setProperty('--grid-size', gridSize);
// render grid
grid.append(fragmentWrapper);
.grid {
display: grid;
grid-template-columns: repeat(calc(var(--grid-size) + 1), 1fr);
/* using CSS grid size (set in JS) */
gap: .25rem;
}
.cell {
display: flex;
align-items: center;
/* align content */
justify-content: center;
/* align content */
aspect-ratio: 1/1;
/* make cell square */
border: 1px solid #d4d4d4;
/* show cell borders */
}
.cell.select {
background-color: tomato;
color: white;
font-weight: bold;
}
<div class="grid"></div>