var isNN = (navigator.appName.indexOf("Netscape")!=-1);
			
			function autoTab(input,len, e) {
				var keyCode = (isNN) ? e.which : e.keyCode; 
				var filter = (isNN) ? [0,8,9] : [0,8,9,16,17,18,37,38,39,40,46];
				if(input.value.length >= len && !containsElement(filter,keyCode)) {
					input.value = input.value.slice(0, len);
					input.form[(getIndex(input)+1) % input.form.length].select();
					input.form[(getIndex(input)+1) % input.form.length].focus();
				}				

			function containsElement(arr, ele) {
				var found = false, index = 0;
				while(!found && index < arr.length)
				if(arr[index] == ele)
					found = true;
				else
					index++;
				return found;
			}	
	
			function getIndex(input) {
				var index = -1, i = 0, found = false;
				while (i < input.form.length && index == -1)
					if (input.form[i] == input)index = i;
					else i++;
				return index;
				}
				return true;
			}