function adjustQty(el, index, method) { 
	if (el.length>1) {
		el = el[index]
	}
	if(checkQty(el.value)){
		if (method=="increase") {
			el.value++;
		}
		else if (method=="decrease"){
			if(el.value>0){
				el.value--;
			}
		}
	} else {
		el.value="1";
		el.focus();
	}
}
function checkQty(v) {
	if ((!validQty(v))||(v<0)) {
		alert('You have entered an invalid quantity!');
		return false
	} else {
		return true
	}
}
function validQty(v) {
    	if (isNaN(v.replace(/ /g,""))) {
    		return false;
    	}
    	else return true;
}