为什么！document.querySelectorAll不适用于多个ID

Question

I currently have this working , but i need to add an additional element so i switched to SelectorAll , but it doesn't work

This is working

if(!document.getElementById('body_options_45')) {
//Do Stuff
}

When i add a 2nd ID and switch to selectorALl , it stops working

if(!document.querySelectorAll('#body_options_45, #body_options_113')) {
   //Do Stuff
}

What am i missing here ?

Answer 1

querySelectorAll returns a NodeList . You will need to check the length like this: if (!document.querySelectorAll('#body_options_45, #body_options_113').length)

Answer 2

querySelectorAll() returns a NodeList . NodeLists are not arrays but, in this particular case, the behavour is the same: empty arrays and empty NodeLists are both truthy .

![] //returns false

!emptyNodeList //returns false

To check if your NodeList is empty or not, use the length property:

if(document.querySelectorAll('#body_options_45, #body_options_113').length===0) {
   //do stuff
}