function checkform(of)
{
	if(!document.getElementById || !document.createTextNode){return;}
	if(!document.getElementById('required')){return;}

	var errorID='errormsg';
	var errorClass='error'
	var errorMsg='Complete los campos marcados con el simbolo ';
	var errorImg='images/style_atencion.gif';
	var errorAlt='Error';
	var errorTitle='Este campo tiene un error!';
	var reqfields=document.getElementById('required').value.split(',');

	if(document.getElementById(errorID))
	{
		var em=document.getElementById(errorID);
		em.parentNode.removeChild(em);
	}
	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='';
	}
	for(var i=0;i<reqfields.length;i++)
	{
		var f=document.getElementById(reqfields[i]);
		if(!f){continue;}
		switch(f.type.toLowerCase())
		{
			case 'text':
				if(f.value=='' && f.id!='email'){cf_adderr(f)}							
				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);

function cf_adderr(o)
	{
		var errorIndicator=document.createElement('img');
		errorIndicator.alt=errorAlt;
		errorIndicator.hspace=4;
		errorIndicator.height=16;
		errorIndicator.align='absmiddle';
		errorIndicator.src=errorImg;
		errorIndicator.title=errorTitle;
		o.className=errorClass;
		o.parentNode.insertBefore(errorIndicator,o);

		if(!document.getElementById(errorID))
		{
			var em=document.createElement('div');
			em.id=errorID;
			var newp=document.createElement('p');
			newp.appendChild(document.createTextNode(errorMsg))

			newp.appendChild(errorIndicator.cloneNode(true));
			em.appendChild(newp);

			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);
			}	
		} 
	}
	function cf_isEmailAddr(str) 
	{
	    return str.match(/^[\w-]+(\.[\w-]+)*@([\w-]+\.)+[a-zA-Z]{2,7}$/);
	}
}