Simple -+ button for javascript text input

Question

I've got this script which I'm using with succes, but I've tried, and failed, to get it to stop making negative numbers when substracting pass 0..

<script language="javascript" type="text/javascript">
currentvalue = 1;
function setUp() {
document.getElementById("qty").value = currentvalue;
}
function addOne() {
currentvalue++;
document.getElementById("qty").value = currentvalue;
}
function subtractOne() {
currentvalue--;
document.getElementById("qty").value = currentvalue;
}
</script>

<input type="text" name="qty" id="qty" maxlength="12" value="1" title="qyu" class="input-text qty" />
<div onload="setUp()">
<input class="qtyplus" type="button" value="" onClick="addOne()">
<input class="qtyminus" type="button" value="" onClick="subtractOne()">
</div>

Anyone got the magic part which stop's the show at 0 ?

Thanks!

Answer 1

Just add an if statement here is the fiddle

and here is your subtractOne function

function subtractOne() {
    if(document.getElementById("qty").value !== '0') {
currentvalue--;
document.getElementById("qty").value = currentvalue;
    }