Run a function getting uncaught type error line 24

Question

The message when I run the function is 'Cannot read properties of null ("reading add"). I think the problem is how I am using a parameter to hold the location of the select tag I want adding to. Thanks Graeme
https://code.sololearn.com/WoEpI59UYMv3/?ref=app

Answer 1

try this

alert("load in function");

var opt = [1, 56];
alert(opt);

addOption(opt[1], selTmp);

function addOption(inText, inLocation){
var x = document.getElementById("selTmp");
var option = document.createElement("option");
option.text = inText;
x.add(option);
}

Answer 2

addOption(opt[1], "selTmp");

and an end tag </body>