Count to target with JavaScript

I'm looking for (and be as brutal as you like) ways to improve the code or the algorithm (I'm aware there should be comments) - I'm a recreational programmer and would like to be improving my skills. My next step is to get the targetNumber value from a nearby file without losing the current count.

 
 
 
  Count to a particular target 
 
 
Starting 

    currentValue = 100;
    targetValue = 1500;

    function count() {
        if (currentValue > targetValue) {
        currentValue -= 1
        } else if (currentValue  
 

function count(from, to, targetElem) {
    targetElem.innerHTML = 'Total wordcount: ' + from;

    if (from == to) return;

    from < to ? from++ : from--; 

    var changeTime = Math.max(20, 1000 - Math.abs(from - to)) / 2;

    setTimeout(function() {count(from, to, target);}, changeTime);
}

count(50, 0, document.getElementById("t"));

A few notes:

• avoid global variables to conserve state - use function arguments instead

• always use var to declare variables. Otherwise they are in the global scope and you don't want this

• added error checking (i.e. whether values are numeric and target is valid) might not be a bad idea, I left it out for clarity here

• return early on known conditions, this reduces complexity in the function body

• the ternary operator condition ? ifTrue : ifFalse can be used in other ways than assigning a value

StackExchange Code Review Q#2669, answer score: 4