I dropped my iphone 4s and now the screen is glitched purple?

I want to fix the screen but, i want to turn it off first. How can i do this.

Get the screen fixed

To do this it is actually extremely simple! Hold the power button (button that powers on the phone) and the home button (circle button near the bottom of the device) at the same exact time for about 10 seconds. After ten seconds, the phone will turn completely off, allowing you to open the phone up for repair, but be careful, as you may easily break the phone beyond repair.