GetElementByClassName() - Is Not A Function

I expected the code below to change Random1 and Random2 to Random but its not doing anything. When I checked developers tool in chrome, it showed 'document.getElementByClassName is

Solution 1:

You should use getElementsByClassName instead using getElementByClassName. It seems you misspelled.

Solution 2:

It seems to be an undefined function you used to call

The class based selection returns an array of objects which is because of multiple elemnts have same class so the function should be getElementsByClassName instead you used getElementByClassName If it is for Id selector getElementById is enough because there is only instance might be there in the DOM