function checkform(of)
		{
		// Test if DOM is available and there is an element called required
			if(!document.getElementById || !document.createTextNode){return;}
			if(!document.getElementById('required')){return;}

		// Define error messages and split the required fields
			var errorID='errormsg';
			var errorClass='error'
/* changes for linked list */
			var errorMsg='Пожалуйста, проверьте правильность заполнения следующих полей:';
/* end changes for linked list */
			var errorImg='images/error.gif';
			var errorAlt='Error';
			var errorTitle='This field has an error!';
			var reqfields=document.getElementById('required').value.split(',');

		// Cleanup old mess
			// if there is an old errormessage field, delete it
			if(document.getElementById(errorID))
			{
				var em=document.getElementById(errorID);
				em.parentNode.removeChild(em);
			}
			// remove old images and classes from the required fields
			for(var i=0;i<reqfields.length;i++)
			{
				var f=document.getElementById(reqfields[i]);
				if(!f){continue;}
				//if(f.previousSibling && /img/i.test(f.previousSibling.nodeName))
				//{
					//f.parentNode.removeChild(f.previousSibling);
				//}
				//f.className='';
				f.style.background='#FFFFFF';
			}
		// loop over required fields
			for(var i=0;i<reqfields.length;i++)
			{
		// check if required field is there
				var f=document.getElementById(reqfields[i]);
				if(!f){continue;}
		// test if the required field has an error, 
		// according to its type
				switch(f.type.toLowerCase())
				{
					case 'text':
						if(f.value=='' && f.id!='email'){cf_adderr(f)}							
		// email is a special field and needs checking
						if(f.id=='email' && !cf_isEmailAddr(f.value)){cf_adderr(f)}							
					break;
					case 'textarea':
						if(f.value==''){cf_adderr(f)}							
					break;
					case 'checkbox':
						if(!f.checked){cf_adderr(f)}							
					break;
					case 'select-one':
						if(!f.selectedIndex && f.selectedIndex==0){cf_adderr(f)}							
					break;
				}
			}
			return !document.getElementById(errorID);

			/* Tool methods */
			function cf_adderr(o)
			{
				// create image, add to and colourise the error fields
				//var 
				//errorIndicator=document.createElement('img');
				//errorIndicator.alt=errorAlt;
				//errorIndicator.src=errorImg;
				//errorIndicator.title=errorTitle;
				o.style.background='#fcc';
				//o.setAttribute('class','error');
				//o.className=errorClass;
				//o.parentNode.insertBefore(errorIndicator,o);

			// Check if there is no error message
				if(!document.getElementById(errorID))
				{
				// create errormessage and insert before submit button
					var em=document.createElement('div');
					em.id=errorID;
					var newp=document.createElement('p');
					newp.appendChild(document.createTextNode(errorMsg))
					em.appendChild(newp);
/* added for linked list */
					var newul=document.createElement('ul');		
					em.appendChild(newul);
/* end added for linked list */
					// find the submit button 
					for(var i=0;i<of.getElementsByTagName('input').length;i++)
					{
						if(/submit/i.test(of.getElementsByTagName('input')[i].type))
						{
							var sb=of.getElementsByTagName('input')[i];
							break;
						}
					}
					if(sb)
					{
						sb.parentNode.insertBefore(em,sb);
					}	
				} 
/* added for linked list */
				var em=document.getElementById(errorID).getElementsByTagName('ul')[0];
				var newli=document.createElement('li');
				var newa=document.createElement('a');
				for(var i=0;i<of.getElementsByTagName('label').length;i++)
				{
					if(of.getElementsByTagName('label')[i].htmlFor==o.id)
					{
						var txt=of.getElementsByTagName('label')[i].firstChild.nodeValue;
						break;
					}
				}
	
				newa.appendChild(document.createTextNode(txt));
				newa.href='#'+f.id;
				newa.onclick=function()
				{
					var loc=this.href.match(/#(\w.+)/)[1];
					document.getElementById(loc).focus();
					return false;
				}
				newli.appendChild(newa);
				em.appendChild(newli);
/* end added for linked list */
			}
			function cf_isEmailAddr(str) 
			{
			    return str.match(/^[\w-]+(\.[\w-]+)*@([\w-]+\.)+[a-zA-Z]{2,7}$/);
			}
		}