function ismaxlength(obj)
{
	var mlength=obj.getAttribute? parseInt(obj.getAttribute("maxlength")) : ""
	if (obj.getAttribute && obj.value.length>mlength)
		obj.value=obj.value.substring(0,mlength)
}

function trim(cadena)
{
	for(i=0; i<cadena.length; )
	{
		if(cadena.charAt(i)==" ")
			cadena=cadena.substring(i+1, cadena.length);
		else
			break;
	}

	for(i=cadena.length-1; i>=0; i=cadena.length-1)
	{
		if(cadena.charAt(i)==" ")
			cadena=cadena.substring(0,i);
		else
			break;
	}
	
	return cadena;
}