/* 
   originally from intandemld.com, but they were bought out and I didn't 
   know how long the domain would remain active, so I copied it locally
*/

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].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;
}