How to populate the options of a select element in javascript

The code:

var newSelect=document.createElement('select');
index=0;
var optn = document.createElement("option");

//langArray is an array that contains different items..the size
//is not fixed for this array.

for(element in langArray)
{
   //Now i want to assign each item in langArray to each option tag
   //will it be sumthng like "optn.options[index]=new Option("Sports", "sportsvalue", true,  false);
   //optn.accept(langArray[0]);
   index++;
}

I'm trying to get options populated by this way but its not coming all right as I don't know how to populate the options from an array in JS. Do I even have to use the loop or can I just assign the langArray to some property of select element and every thing will be up and running?

You can create the option inside the loop;

for(element in langArray)
{
   var opt = document.createElement("option");
   opt.value= index;
   opt.innerHTML = element; // whatever property it has

   // then append it to the select element
   newSelect.appendChild(opt);
   index++;
}

// then append the select to an element in the dom

2023 Update:

To make sure we avoid creating globals and remain in the correct scope, we can use map() and let.

let selectTag = document.createElement('select');
langArray.map( (lang, i) => {
    let opt = document.createElement("option");
    opt.value = i; // the index
    opt.innerHTML = lang;
    selectTag.append(opt);
});