In this paper, we report for the first time the spontaneous formation of Zr-based metallic glass nanofilms by developed dynamic forced-shear-rupture technique of hat-shaped specimens. The obtained nanofilms have about 100 nm thickness and other two geometrical dimensions can reach micrometer scales. Their glassy nature and structural stability were solidly identified. It was found that electrons with the wavelength of less than 0.165 angstrom could make the metallic glass nanofilms transparent. Furthermore, it is clearly shown that shear-banding instability still afflicts such 100-nm-thick metallic glass nanofilms. This paper was published as: Jiang MQ; Duan GH; Dai LH. Metallic glass nanofilms. JOURNAL OF NON-CRYSTALLINE SOLIDS, 357(7):1621-1627(2011)