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JavaScript AJAX Basics Programming AJAX Processing JSON Data

Posted by Agata Zurek
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Agata Zurek
Full Stack JavaScript Techdegree Graduate 26,419 Points

Could anyone have a look and comment on my refactoring to avoid innerHTML

I was reading on mdn that using .innerHTML is frowned upon so I wanted to refactor this exercise to avoid using it. I would appreciate some feedback if I followed best practices. I also made sure to use const instead of var. Thanks!

const xhr = new XMLHttpRequest();

xhr.onreadystatechange = function () {
  if (xhr.readyState === 4) {
    const employees = JSON.parse(xhr.responseText);
    const list = document.createElement('ul');

    list.className = "bulleted";
    document.getElementById('employeeList').appendChild(list);

    for (let i = 0; i < employees.length; i++) {
      const listItem = document.createElement('li');
      if (employees[i].inoffice === true) {
        listItem.className = "in";
      } else {
         listItem.className = "out";
      }  
        listItem.innerText = employees[i].name
        list.appendChild(listItem);
    }
  }
};

xhr.open('GET', 'data/employees.json');
xhr.send();
Janelle Mackenzie
Janelle Mackenzie
7,510 Points

I like this approach better!

2 Answers

Steven Parker
Steven Parker
231,275 Points
Steven Parker
Steven Parker
231,275 Points

Perhaps "frowned upon" isn't entirely accurate. MDN says:

Setting the value of innerHTML lets you easily replace the existing contents of an element with new content.

But for security reasons, you might want to avoid it if your intention is to insert user-supplied text onto the page.

And since you're not intending to insert any markup anyway, using innerText instead is a good design choice. :+1:

Agata Zurek
.a{fill-rule:evenodd;}techdegree seal-36
Agata Zurek
Full Stack JavaScript Techdegree Graduate 26,419 Points

Thank you for having a look and for your feedback!

I was referring to this warning from mdn

Warning: If your project is one that will undergo any form of security review, using innerHTML most likely will result in your code being rejected. For example, if you use innerHTML in a browser extension and submit the extension to addons.mozilla.org, it will not pass the automated review process.

Steven Parker
Steven Parker
231,275 Points
Steven Parker
Steven Parker
231,275 Points

Of course, an automated review process isn't intelligent enough to discern a potential issue from a non-issue based on the data source. But if you're not submitting a mozilla add-on, or working where rigid coding standards prohibit it, using "innerHTML" appropriately should be fine.

But you're right that a "best practice" would be to use "innerText" instead anytime the content doesn't have to accommodate markup.

Piotr Manczak
seal-mask
.a{fill-rule:evenodd;}techdegree seal-36
Piotr Manczak
Front End Web Development Techdegree Graduate 29,367 Points
Piotr Manczak
.a{fill-rule:evenodd;}techdegree seal-36
Piotr Manczak
Front End Web Development Techdegree Graduate 29,367 Points

I accidentally created something similar: 

const xhr = new XMLHttpRequest();
xhr.onreadystatechange = function() {
  if ( xhr.readyState === 4 ) {
    let employees = JSON.parse(xhr.responseText);
    let list = document.getElementById('employeeList');
    let ul = document.createElement('ul');
    ul.className = 'bulleted';
    list.appendChild(ul);
    for (let i=0; i<employees.length; i++) {
      let employee = employees[i];
      let li = document.createElement('li');
      li.textContent = employee.name;
      if ( employee.inoffice == true ) {
        li.className = 'in';
      } else {
        li.className = 'out';
      }
      ul.appendChild(li);
    }
  }
};
xhr.open('GET', 'data/employees.json');
xhr.send();