javascript - Cannot read property '...' of null

Question

I'm having this code over here and I'm pretty sure I've passed the name properly but it still says as null:

var w = window.innerWidth;
var h = window.innerHeight;
var inj = document.getElementById("sterile").innerHTML;

function inject(data) {
    document.getElementById("sterile").innerHTML+=data;
}

function geth(elem) {
    return document.getElementById(elem).clientHeight;
}

inject( ".fullscreen { height:"+h+"px;}");

inject( ".headpad {padding-top:"+h-(geth("headwrap")/2)+"px;}");

I tried typing geth("sterile") onto the Chrome's devconsole and it returns properly but when I launch this through a file I always get Uncaught TypeError....

The error line was 10.

Answer 1

Assuming you're including your javascript in the head tag, try including it just before the </body> tag instead. This ensures that the browser is aware of all elements by the time it parses your javascript.