function Calcularwidth(){		
		
    var curr_width = document.getElementById("contenido-principal").offsetWidth;
	
		// ========================
        // Customise these variables as you wish
        // ========================
		var _resizeClass  = 'imagenancha';

        var _resizeWidth  = curr_width - 13;
        var oContainer = document.getElementById("contenido-principal");
        
		var imgArray = oContainer.getElementsByTagName( 'IMG' );

        for ( var i = 0; i < imgArray.length; i++ )
        {
            var imgObj = imgArray[i];

            if ( imgObj.className == _resizeClass ) 
			//if ( imgObj.offsetWidth > _resizeWidth ) todas las imagenes desactivado ya que despues quedan chicas y no crecen
            {
                imgObj.style.width = _resizeWidth + 'px';
            }
        }

	document.getElementById("sidebar-secundaria").style.right = 0 + "px";
}

window.onload = Calcularwidth;
window.onresize = Calcularwidth;