function isempty(emptyvar) {
	if(emptyvar == '' || emptyvar == null) {
		return true;
	}                      
}

function echeck(str) {
    var at="@";
	var dot=".";
	var lat=str.indexOf(at);
	var lstr=str.length;
	var ldot=str.indexOf(dot);
	if (str.indexOf(at)==-1){
	   return false;
	}
    
	if(str.indexOf(at)==-1 || str.indexOf(at)==0 || str.indexOf(at)==lstr){
        return false;
	}
    
	if (str.indexOf(dot)==-1 || str.indexOf(dot)==0 || str.indexOf(dot)==lstr){
        return false;
	}
	
    if (str.indexOf(at,(lat+1))!=-1){
        return false;
    }
     
	 if (str.substring(lat-1,lat)==dot || str.substring(lat+1,lat+2)==dot){
	    return false;
	 }
     
	 if (str.indexOf(dot,(lat+2))==-1){
        return false;
	 }
	
	 if (str.indexOf(" ")!=-1){
	    return false;
     }

    return true;				
	}

function show(field) {
    document.getElementById(field).style.borderColor = '#ff0000';
}

function hide(field) {
    document.getElementById(field).style.borderColor = '#F6F3F3';
}

function isNumeric(x) {
    var RegExp = /^(-)?(\d*)(\.?)(\d*)$/;
    var result = x.match(RegExp);
    if(result == null) return true;
}

    function checkForm() {
	var surname = document.getElementById('surname').value;
	var name = document.getElementById('name').value;
	var address = document.getElementById('address').value;
	var city = document.getElementById('city').value;
	var telephone = document.getElementById('telephone').value;
	var email = document.getElementById('email').value;
	var hoe1 = document.getElementById('hoe1').value;
	var hoe2 = document.getElementById('hoe2').value;
	var hoe3 = document.getElementById('hoe3').value;
	var hoe4 = document.getElementById('hoe4').value;
	var someoneyes = document.getElementById('someoneyes').value;
	var someoneno = document.getElementById('someoneno').value;
	var interested = document.getElementById('interested').value;
	var placeyes = document.getElementById('placeyes').value;
	var placeno = document.getElementById('placeno').value;
	var buyyes = document.getElementById('buyyes').value;
	var buyno = document.getElementById('buyno').value;
	var contactyes = document.getElementById('contactyes').value;
	var contactno = document.getElementById('contactno').value;
	var miss = document.getElementById('miss').value;
	var different = document.getElementById('different').value;
	var informedyes = document.getElementById('informedyes').value;
	var informedno = document.getElementById('informedno').value;
    var years = document.getElementById('years').value;
	var error = 0;

    hide('surname');
    hide('name')
    hide('address');
    hide('city');
    hide('telephone');
    hide('email');
    hide('how');
    hide('somebody');
    hide('interested');
    hide('place');
    hide('buy');
    hide('contact1');
    hide('miss');
    hide('different');
    hide('informed');
    hide('years');

	if(isempty(surname)) { error++;show('surname'); }
	if(isempty(name)) { error++;show('name'); }
	if(isempty(address)) { error++;show('address'); }
	if(isempty(city)) { error++;show('city'); }
	if(isempty(telephone)) { error++;show('telephone'); }
    if((document.forms[0].magazine.checked == false) && (document.forms[0].internet.checked == false) && (document.forms[0].other.checked == false) && (document.forms[0].somebodyelse.checked == false)) { error++;show('how'); }
	if((document.forms[0].someoneyes.checked == false) && (document.forms[0].someoneno.checked == false)) { error++;show('somebody'); }
	if(isempty(interested)) { error++;show('interested'); }
	if((document.forms[0].placeyes.checked == false) && (document.forms[0].placeno.checked == false)) { error++;show('place'); }
	if((document.forms[0].buyyes.checked == false) && (document.forms[0].buyno.checked == false)) { error++;show('buy'); }
    if((document.forms[0].contactyes.checked == false) && (document.forms[0].contactno.checked == false)) { error++;show('contact1'); }
	if(isempty(miss)) { error++;show('miss'); }
	if(isempty(different)) { error++;show('different'); }
	if((document.forms[0].informedyes.checked == false) && (document.forms[0].informedno.checked == false)) { error++;show('informed'); }
    if(echeck(email) == false) { error++;show('email'); }
    if(isempty(years)) { error++;show('years'); }
            
	if(error > 0) {
		alert('All fields must be filled in.');
	} else {
        document.forms[0].submit();
    }
}