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Cannot read property 'classList' of undefined

GutoTrosla answered on July 20, 2020 Popularity 10/10 Helpfulness 2/10

answer Cannot read property 'classList' of undefined

Cannot read property 'classList' of undefined

Comment

It means that document.getElementById("lastName") is returning undefined and you're trying to call classList on undefined itself.

In your HTML input has the attribute name which equals lastName but there is no actual id="lastname"

Either add the attribute id to your input or change getElementById to getElementsByName.

Note that getElementsByName doesn't return a single item.

Popularity 10/10 Helpfulness 2/10 Language javascript

Source: stackoverflow.com

Tags: javascript undefined

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