function validateField(field_id){

    var validated = false;
    
    var first_value = document.getElementById(field_id).value;
    
    if (first_value.length == 0) {
    
        //                focusOnElement(field_id);
        
        validated = false;
        
    }
    else {
    
        validated = true;
        
    }
    
    return validated;
    
}



function validateEmailField(field_id){

    var validated = false;
    
    var fieldValidated = validateField(field_id);
    
    if (fieldValidated) {
    
        var validRegExp = /^([A-Za-z0-9_\-\.])+\@([A-Za-z0-9_\-\.])+\.([A-Za-z]{2,4})$/;
        
        ///^.+@.+\..+$/;
        
        var strEmail = document.getElementById(field_id).value;
        
        if (strEmail.search(validRegExp) == -1) {
        
            //                    focusOnElement(field_id);
            
            validated = false;
            
        }
        else {
        
            validated = true;
            
        }
        
    }
    
    return validated;
    
}



function validateEmailField2(field_id){

    var validated = false;
    
    var fieldValidated = validateField(field_id);
    
    if (fieldValidated) {
    
        var validRegExp = "/^.+@.+\..+$/";
        
        var strEmail = document.getElementById(field_id).value;
        
        if (strEmail.search(validRegExp) == -1) {
        
            //                    focusOnElement(field_id);
            
            validated = false;
            
        }
        else {
        
            validated = true;
            
        }
        
    }
    
    return validated;
    
}



function isIntegerById(id){

    var fieldValidated = validateField(id);
    
    if (fieldValidated) {
    
        var s = document.getElementById(id).value;
        
        var i;
        
        for (i = 0; i < s.length; i++) {
        
            // Check that current character is number.
            
            var c = s.charAt(i);
            
            if (((c < "0") || (c > "9"))) 
                return false;
            
        }
        
        // All characters are numbers.
        
        return true;
        
    }
    else {
    
        return false;
        
    }
    
    
    
}



function IsNumericById(id){

    var fieldValidated = validateField(id);
    
    if (fieldValidated) {
    
    
    
        var sText = document.getElementById(id).value;
        
        var ValidChars = "0123456789.";
        
        var IsNumber = true;
        
        var Char;
        
        
        
        for (i = 0; i < sText.length && IsNumber == true; i++) {
        
            Char = sText.charAt(i);
            
            if (ValidChars.indexOf(Char) == -1) {
            
                IsNumber = false;
                
            }
            
        }
        
        return IsNumber;
        
    }
    else {
    
        return false
        
    }
    
}





function IsNumeric(sText){

    var ValidChars = "0123456789.";
    
    var IsNumber = true;
    
    var Char;
    
    
    
    for (i = 0; i < sText.length && IsNumber == true; i++) {
    
        Char = sText.charAt(i);
        
        if (ValidChars.indexOf(Char) == -1) {
        
            IsNumber = false;
            
        }
        
    }
    
    return IsNumber;
    
}





//Date validation helper scripts

var dtCh = "/";

var minYear = 1900;

var maxYear = 2100;



function isInteger(s){

    var i;
    
    for (i = 0; i < s.length; i++) {
    
        // Check that current character is number.
        
        var c = s.charAt(i);
        
        if (((c < "0") || (c > "9"))) 
            return false;
        
    }
    
    // All characters are numbers.
    
    return true;
    
}







function stripCharsInBag(s, bag){

    var i;
    
    var returnString = "";
    
    // Search through strings characters one by one.
    
    // If character is not in bag, append to returnString.
    
    for (i = 0; i < s.length; i++) {
    
        var c = s.charAt(i);
        
        if (bag.indexOf(c) == -1) 
            returnString += c;
        
    }
    
    return returnString;
    
}



function daysInFebruary(year){

    // February has 29 days in any year evenly divisible by four,
    
    // EXCEPT for centurial years which are not also divisible by 400.
    
    return (((year % 4 == 0) && ((!(year % 100 == 0)) || (year % 400 == 0))) ? 29 : 28);
    
}

function DaysArray(n){

    for (var i = 1; i <= n; i++) {
    
        this[i] = 31
        
        if (i == 4 || i == 6 || i == 9 || i == 11) {
            this[i] = 30
        }
        
        
        
        if (i == 2) {
            this[i] = 29
        }
        
    }
    
    return this
    
}



function isDate(dtStr){

    var daysInMonth = DaysArray(12)
    
    var pos1 = dtStr.indexOf(dtCh)
    
    var pos2 = dtStr.indexOf(dtCh, pos1 + 1)
    
    var strMonth = dtStr.substring(0, pos1)
    
    var strDay = dtStr.substring(pos1 + 1, pos2)
    
    var strYear = dtStr.substring(pos2 + 1)
    
    strYr = strYear
    
    if (strDay.charAt(0) == "0" && strDay.length > 1) 
        strDay = strDay.substring(1)
    
    if (strMonth.charAt(0) == "0" && strMonth.length > 1) 
        strMonth = strMonth.substring(1)
    
    for (var i = 1; i <= 3; i++) {
    
        if (strYr.charAt(0) == "0" && strYr.length > 1) 
            strYr = strYr.substring(1)
        
    }
    
    month = parseInt(strMonth)
    
    day = parseInt(strDay)
    
    year = parseInt(strYr)
    
    if (pos1 == -1 || pos2 == -1) {
    
        alert("The date format should be : mm/dd/yyyy")
        
        return false
        
    }
    
    if (strMonth.length < 1 || month < 1 || month > 12) {
    
        alert("Please enter a valid month")
        
        return false
        
    }
    
    if (strDay.length < 1 || day < 1 || day > 31 || (month == 2 && day > daysInFebruary(year)) || day > daysInMonth[month]) {
    
        alert("Please enter a valid day")
        
        return false
        
    }
    
    if (strYear.length != 4 || year == 0 || year < minYear || year > maxYear) {
    
        alert("Please enter a valid 4 digit year between " + minYear + " and " + maxYear)
        
        return false
        
    }
    
    if (dtStr.indexOf(dtCh, pos2 + 1) != -1 || isInteger(stripCharsInBag(dtStr, dtCh)) == false) {
    
        alert("Please enter a valid date")
        
        return false
        
    }
    
    return true
    
}

//END - Date validation helper scripts



function focusOnElement(element_id){

    document.getElementById(element_id).focus();
    
}



function showHideTag(field_id, show){

    if (show) {
    
        document.getElementById(field_id).style.display = "";
        
    }
    else {
    
        document.getElementById(field_id).style.display = "none";
        
    }
    
}

<!--

function check_required_8(){

    if (!document.getElementById('field_26').value) {
        alert('Required field "Email" is empty');
        document.getElementById('field_26').focus();
        return false;
    }
    if (!validateEmailField('field_26')) {
        alert('Please, enter valid email');
        document.getElementById('field_26').focus();
        return false;
    }
    if (!document.getElementById('field_24').value) {
        alert('Required field "Name" is empty');
        document.getElementById('field_24').focus();
        return false;
    }
    
    document.cf8form.submit();
    
    alert("Form data was submitted successfully.");
    
}