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JavaScript JavaScript and the DOM Making Changes to the DOM Get and Set Content with textContent and innerHTML

Ryan Miles
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Ryan Miles
Full Stack JavaScript Techdegree Student 3,261 Points
Posted by Ryan Miles
.a{fill-rule:evenodd;}techdegree
Ryan Miles
Full Stack JavaScript Techdegree Student 3,261 Points

selecting the button with getElementById works, but using querySelector is returning null.

When I assign the 'btn-main' to a variable using 

const btnMain = document.getElementById('btn-main');

Everything works as expected. However using

const btnMain = document.querySelector('.btn-main');

returns null. How should I properly using querySelector to select the button?

2 Answers

Jason Larson
Jason Larson
8,353 Points

You are probably using querySelector correctly, but you have the wrong value. You have '.btn-main', which would be correct if you were selecting something with a class of 'btn-main'. Values in the querySelector method are like CSS definitions. Since you are trying to select an item with an ID of 'btn-main', you want to use:

const btnMain = document.querySelector('#btn-main');

Note that you don't have to make this distinction with getElementById because you are already explicitly saying that you are going to be using the ID, so there's no need to make a special differentiation in the parameter.

Erik Biebinger
Erik Biebinger
7,299 Points
Erik Biebinger
Erik Biebinger
7,299 Points

I had this issue too, because I did not update my html correctly. I am not sure if Guil is mentioning the change of the button id into a class. If so, sorry, my mistake.