DOM Creating content

Create Content

You can create a div element an set the content.

We use the document method createElement and the DOM node method append

Change the code so that it says 'Hello world'

let e = document.createElement('div');
e.innerHTML = 'Hello';
document.body.append(e);

let e = document.createElement('div');
e.innerHTML = 'Hello world';
document.body.append(e);

Create img

You can create a img element and set the src. In this example you must set the src and the style of the new element a.

a.style = 'width:100px;border:solid;';

These are CSS properties.

let a = document.createElement('img');
a.src = '/flags/fr.png';
document.body.append(a);

let a = document.createElement('img');
a.src = '/flags/fr.png';
a.style = 'width:100px;border:solid;';
document.body.append(a);

Create multiple elements

• You can add several elements to the document.body.
• You can add elements to other elements.
• Change this code to match the model answer
• Can you see why the flag does not show?

let a = document.createElement('div');
a.innerHTML = 'Germany, ';
let b = document.createElement('i');
b.innerHTML = 'Berlin';
a.appendChild(b);
document.body.append(a);
let c = document.createElement('img');
c.src = '/flags/de.png';
c.style = 'width:100px';

let a = document.createElement('div');
a.innerHTML = 'Germany, ';
let b = document.createElement('i');
b.innerHTML = 'Berlin';
a.append(b);
document.body.appendChild(a);
let c = document.createElement('img');
c.src = '/flags/de.png';
c.style = 'width:100px';
document.body.append(c);

Setting complex innerHTML

You can put more complex HTML into an element. The backticks ` ` can span many lines.

Make the flags bigger - you can set the height to 2ex

let a = document.createElement('div');
a.innerHTML = `
  <img src='/flags/gr.png' style='height:1ex'>
  Greece <i>Athens</i>`;
document.body.appendChild(a);
let b = document.createElement('div');
b.innerHTML = `
  <img src='/flags/it.png' style='height:1ex'>
  Italy <i>Rome</i>`;
document.body.appendChild(b);

let a = document.createElement('div');
a.innerHTML = `
  <img src='/flags/gr.png' style='height:2ex'>
  Greece <i>Athens</i>`;
document.body.appendChild(a);
let b = document.createElement('div');
b.innerHTML = `
  <img src='/flags/it.png' style='height:2ex'>
  Italy <i>Rome</i>`;
document.body.appendChild(b);

Using functions

• You should avoid copying chunks of code.
• A well chosen function can help avoid that.
• Notice how string interpolation allows you to include variables in the string.

function addCountryDiv(name, capital, flag){
  let a = document.createElement('div');
  a.innerHTML = `
    <img src='/flags/${flag}.png'
         style='height:2ex;'>
    ${name}`;
  document.body.appendChild(a);
}

addCountryDiv('China', 'Beijing', 'cn');
addCountryDiv('Japan', 'Tokyo', 'jp');
addCountryDiv('South Korea', 'Seoul', 'kr');

function addCountryDiv(name, capital, flag){
  let a = document.createElement('div');
  a.innerHTML = `
    <img src='/flags/${flag}.png'
         style='height:2ex;border:solid'>
    ${name} <i>${capital}</i>`;
  document.body.appendChild(a);
}

addCountryDiv('China', 'Beijing', 'cn');
addCountryDiv('Japan', 'Tokyo', 'jp');
addCountryDiv('South Korea', 'Seoul', 'kr');

Using a loop

• Another way to avoid copying chunks of code is to use a loop.
• Notice how string interpolation allows you to include variables in the string.

let cl = [{n:'China', c:'Beijing', f:'cn'},
          {n:'Japan', c:'Tokyo',   f:'jp'},
          {n:'South Korea', c:'Seoul', f:'kr'}];
for(let c of cl){
  let a = document.createElement('div');
  a.innerHTML = `
    ${c.name}`;
  document.body.appendChild(a);
}

let cl = [{n:'China', c:'Beijing', f:'cn'},
          {n:'Japan', c:'Tokyo',   f:'jp'},
          {n:'South Korea', c:'Seoul', f:'kr'}];
for(let c of cl){
  let a = document.createElement('div');
  a.innerHTML = `
    <img src='/flags/${c.flag}.png'
         style='height:2ex;border:solid'>
    ${c.name} <i>${c.capital}</i>`;
  document.body.appendChild(a);
}