function roll_over(img_name, img_src)
{
document[img_name].src = img_src;
}

function Check(){

if(!f.person_firstname.value){
alert('Please, fill "Name" field!');
f.person_firstname.focus();
return false;}

if(!f.person_email.value){
alert('Please, fill "E-mail" field!');
f.person_email.focus();
return false;}

var regEmail = /^[\w.-]+@([a-z0-9\-]+\.)+[a-z]{2,6}$/i;

if(!regEmail.test(f.person_email.value))
{
alert('Please, fill "E-mail" field correctly!');
f.person_email.focus();
return false;
}

if(!f.project_descr.value){
alert('Please, fill "Your inquiry" field!');
f.project_descr.focus();
return false;}

jsfield = new String(f.project_descr.value);
if (jsfield.length>500){
alert ('Message must be less more then 500 symbols!');
f.project_descr.value='';
f.project_descr.focus();
return false;}

return true; }

function expandcollapse (postid) { 

   whichpost = document.getElementById(postid); 
   
   if (whichpost.className=='postshown') { 
	  whichpost.className='posthidden'; 
   } 
   else { 
	  whichpost.className='postshown'; 
   } 
}

function displayAnswer (answr) { 
alert ('Correct Answer - ' + answr);
}