onload=function()
{	
	if(screen.width <=800)
	{
		document.body.background="./recursos/img/fondoPagina800.jpg";	
	}
	else 
	{
		if((800 < screen.width) && (screen.width <= 1024))					
		{	
			document.body.background="./recursos/img/fondoPagina1024.jpg";
		}
		else
		{	
			if((1024 < screen.width) && (screen.width <= 1280))
			{
				document.body.background="./recursos/img/fondoPagina1280.jpg";							
			}
			else
			{
				document.body.background="./recursos/img/fondoPagina1680.jpg";				
			}		
		}
	}	
}