Numeric Validation in Javascript

/*
NUMERIC
prefix --> For number of digits before .(Period)
If you didn't give the period also it allows only the digits that given in the prefix part

suffix --> For the number of digits after the .(Period)

NumberOnly
If we specify suffix as 0 it allows only integer
*/

  
function NumericValidation(ctrlName, e, prefix, suffix) {

    var evt = e || window.event;
    var code = e.charCode ? e.charCode : e.keyCode;
    var EndKey = 35;
    var HomeKey = 36;
    var NumeriPeriodKey = 110;
    var PeriodKey = 190;
    if (e.shiftKey || e.ctrlKey) {
        return false;
    }


    //debugger;
    // IE
    if (evt.type == 'keydown') {

        if ((code == EndKey || code == HomeKey || code == 37 || code == 38 || code == 39 || code == 40 || code == 9)) {
            return true;
        }

        if (code == 46 || code == 8) {
            var val = ctrlName.value;
            var pos = val.indexOf('.');
            var lenofBox = val.length;

            if (code == 8) {
                //Since back key deletes backward
                if (doGetCaretPosition(ctrlName) == (pos + 1)) {

                    ctrlName.value = val.substring(0, pos)
                }
                else {
                    return true;
                }
            }
            else (code == 46)
            {
                //Since del key deletes forward
                if (doGetCaretPosition(ctrlName) == pos) {

                    ctrlName.value = val.substring(0, pos)
                }
                else {
                    return true;
                }
            }
        }

        if ((evt.keyCode >= 48 && evt.keyCode <= 57) || (evt.keyCode >= 96 && evt.keyCode <= 105) || (code == PeriodKey || code == NumeriPeriodKey)) {

            var val = ctrlName.value;

            if (val != "") {
                var pos = val.indexOf('.');
                var lenofBox = val.length;

                //To allow only int
                if ((suffix == 0) && (code == PeriodKey || code == NumeriPeriodKey)) {
                    return false;
                }

                //if already period is available
                if ((code == PeriodKey || code == NumeriPeriodKey) && (pos > -1)) {
                    return false;
                }

                //if prefix reaches and the current one is not period the stop the event
                if ((pos == -1 && lenofBox == prefix) && (code != PeriodKey && code != NumeriPeriodKey)) {
                    return false;
                }

                if (doGetCaretPosition(ctrlName) > pos) {

                    if (pos > -1) {
                        var decSting = val.substring(pos + 1, lenofBox + 1);
                        // debugger;
                        //alert(doGetCaretPosition(document.getElementById('TextBox1')));
                        if (decSting.length == suffix) {
                            return false;
                        }
                    }
                }
                else if (pos >= prefix) {
                    return false;
                }

            }

            // alert(document.getElementById('TextBox1').value + String.fromCharCode(evt.keyCode));
            return true;
        }
        else {
            //  alert(document.getElementById('TextBox1').value);
            return false;
        }
    }
    else if (evt.type == 'keypress') {

        if ((code == 37 || code == 38 || code == 39 || code == 40) || (code == 46 || code == 8 || code == 9)) {
            return true;
        }

        if ((evt.keyCode >= 48 && evt.keyCode <= 57) || (evt.keyCode >= 96 && evt.keyCode <= 105) || (code == PeriodKey || code == NumeriPeriodKey)) {

            var val = ctrlName.value;

            if (val != "") {
                var pos = val.indexOf('.');
                var lenofBox = val.length;

                //To allow only int
                if ((suffix == 0) && (code == PeriodKey || code == NumeriPeriodKey)) {
                    return false;
                }

                //if already period is available
                if ((code == PeriodKey || code == NumeriPeriodKey) && (pos > -1)) {
                    return false;
                }

                //if prefix reaches and the current one is not period the stop the event
                if ((pos == -1 && lenofBox == prefix) && (code != PeriodKey || code != NumeriPeriodKey)) {
                    return false;
                }

                if (doGetCaretPosition(ctrlName) > pos) {

                    if (pos > -1) {
                        var decSting = val.substring(pos + 1, lenofBox + 1);
                        // debugger;
                        //alert(doGetCaretPosition(document.getElementById('TextBox1')));
                        if (decSting.length == suffix) {
                            return false;
                        }
                    }
                }
                else if (pos >= prefix) {
                    return false;
                }
            }

            // alert(document.getElementById('TextBox1').value + String.fromCharCode(evt.keyCode));
            return true;
        }
        else {
            //   alert(document.getElementById('TextBox1').value);
            return false;
        }
    }
}

function doGetCaretPosition(ctrl) {
    var CaretPos = 0; // IE Support
    if (document.selection) {
        ctrl.focus();
        var Sel = document.selection.createRange();
        Sel.moveStart('character', -ctrl.value.length);
        CaretPos = Sel.text.length;
    }
    // Firefox support
    else if (ctrl.selectionStart || ctrl.selectionStart == '0') CaretPos = ctrl.selectionStart;
    return (CaretPos);
}