Reverse a dynamic array

Question

I have 'button' like this

<span data-id="dr21" data-minheight="100" data-maxheight="200" data-minwidth="20" data-maxwidth="50"  class="customsizebutton">(edit size)/span>

and script like this

<script>
$('.customsizebutton').click(function ()
{
var id = $(this).data('id');    
var minHeight = $(this).data('minheight');
var maxHeight = $(this).data('maxheight');
var minWidth = $(this).data('minwidth');
var maxWidth = $(this).data('maxwidth');
var arrayH = [];
var arrayW = [];
for (var i = minHeight; i <= maxHeight-1; i++) {
arrayH.push(i);
}
for (var i = minWidth; i <= maxWidth-1; i++) {
arrayW.push(i);
}

var selectListH = document.getElementById("h-"+id);
for (var i = 0; i < arrayH.length; i++) {
var option = document.createElement("option");
 option.text = arrayH[i];
selectListH.appendChild(option);
}

var selectListW = document.getElementById("w-"+id);

for (var i = 0; i < arrayW.length; i++) {
var option = document.createElement("option");
 option.text = arrayW[i];
selectListW.appendChild(option);
}})
</script>

I am trying to fill the two dropdowns with

<option>200</option>
<option>199</option>...    
<option>101</option>
<option>100</option>

<option>50</option>
<option>49</option>...    
<option>21</option>
<option>20</option>

It currently fills the dropdowns the opposite direction (low to high). I'm new to this and trial and error has got me this far.

Thanks

Answer 1

Just populate the arrays in reverse order.

for (var i = maxHeight-1; i >= minHeight; i--) {
arrayH.push(i);
}
for (var i = maxWidth-1; i >= minWidth; i--) {
arrayW.push(i);
}

Answer 2

If you merely need to populate your dropdowns in reverse order, you can just iterate them in reverse, like so:

for (var i = arrayH.length - 1; i >= 0; i--) {
var option = document.createElement("option");
 option.text = arrayH[i];
selectListH.appendChild(option);
}

If you want to actually reverse the items in the array, as the title of your question denotes, that's even easier, with the Array.reverse function:

arrayH = arrayH.reverse();

If you're new, I recommend reviewing the JavaScript documentation over at Mozilla.