if(document.getElementById && document.getElementsByTagName)
{
	window.onload = function()
	{
		var f                = document.getElementById("formContacto");
		var reqFields        = new Array();
		var inputElements    = f.getElementsByTagName("input");
		var textareaElements = f.getElementsByTagName("textarea");
		
		for(var i=0; i<inputElements.length; i++)
		{
			if(inputElements[i].className.indexOf("obligatorio") > -1){ reqFields.push(inputElements[i]); }
		}
		for(var i=0; i<textareaElements.length; i++)
		{
			if(textareaElements[i].className.indexOf("obligatorio") > -1){ reqFields.push(textareaElements[i]); }
		}

		
		f.onsubmit = function()
		{
			var returnVal = true;
			var errors    = new Array();
			
			for(var i=0; i<reqFields.length; i++)
			{
				if(reqFields[i].value == "")
				{
					returnVal = false;
					errors.push(reqFields[i]);
				}
			}
			
			if(errors.length>0)
			{
				var strError = "";
				for(var i=0; i<errors.length;i++)
				{
					strError += "El campo " + String(errors[i].getAttribute("id")).replace(/^f/,"") + " es obligatorio. \n";
				}
				alert(strError)
			}
			return returnVal;
		}
	}
}