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JavaScript Interactive Web Pages with JavaScript JavaScript and the DOM Where to Look for Help - Documentation

Posted by john larson
john larson
16,594 Points

why is it necessary to add the index value to make this work?

I tried to store the body element in a var for something I was experimenting with. It did not work. I can see here the same thing was done successfully adding the index value[0]. I would love to understand why?

function generate_table() {
  // get the reference for the body
  var body = document.getElementsByTagName("body")[0];

the alternate solution someone gave me was... 

document.body.append(ul);

which did work for what I was trying to do

2 Answers

Fábio Nascimento
Fábio Nascimento
10,418 Points
Fábio Nascimento
Fábio Nascimento
10,418 Points

The .getElementsByTagName method returns an array of results, so you get something like '[<body>....</body>]'. To access a value in an array you need its index, that's why.

john larson
john larson
16,594 Points

Thank you

Chyno Deluxe
Chyno Deluxe
16,936 Points
Chyno Deluxe
Chyno Deluxe
16,936 Points

The reason for adding the [0] in the code is because the .getElementsByTagName() method returns an array of all elements with the provided tag name.

An alternative method to use in order to return the first instance of an element would be to use .querySelector("body")

john larson
john larson
16,594 Points

Thank you, that's good to keep in mind also. Many paths, same destination.