html - Fullscreen API change default color -

i'm using fullscreen api , default color border black seen in image:

image http://blogs.sitepointstatic.com/examples/tech/full-screen/index2.html.

i change background color different color. assuming div has id #content, i've tried using

#content::backdrop {   background-color: red; } 

but did not work me.

how change color?

you need use :fullscreen css pseudo-class vendor info. can see nice tutorial example here , docs here.

i've added following your example , worked me:

#myimage:fullscreen {   background-color: green;   width: 100vw;   height: 100vh; }  #myimage:-webkit-full-screen {   background-color: green;   width: 100vw;   height: 100vh; }  #myimage:-moz-full-screen {   background-color: green;   width: 100vw;   height: 100vh; }  #myimage:-ms-fullscreen {   background-color: green;   width: 100vw;   height: 100vh; }