function sizeText(size)
{
		switch(size)
		{
				case 0:
					document.getElementById("DIV_caja").style.fontSize = "1em";
					break;
				case 1:
					document.getElementById("DIV_caja").style.fontSize = "1.3em";				
					break;
				case 2:
					document.getElementById("DIV_caja").style.fontSize = "1.7em";				
					break;
		}
}
function sizeMax() {
    a = document.getElementById("DIV_caja").clientWidth / 16;
    b = document.documentElement.clientWidth / 16;
    c = b / a
    document.getElementById("DIV_caja").style.fontSize = c + 'em';
}