After I turn on the screen and set the link to "https://google.cn" , it is white and never change
And I look up the debug.log. There is no any error about MCEF or WebDisplays
MCEF: 1.31
WebDisplays:: 1.1
MineCraft: 1.12.2
OS: Windows10-64Bit
Thanks for your reply!

I think it may not successfully download JCEF......Where should I download the complete JCEF?

Hi, what is your hardware setup? What GPU do you have?

My graphics card is AMD Radeon R5 M230 series.(Maybe I misunderstood the meaning of GPU?)
In mcef.cfg，CefArgs option is "--disable-gpu"，Do I need to make any changes to this?

Yes, try removing that CEF option and see if you have the same result. --disable-gpu should not be necessary

It is white too
After I remove the option
There is no any error in debug.log too

You can try these builds https://github.com/jcefbuild/jcefbuild/releases

Hmmm......After I use the package provide by another one, it is normal. There are JCEF and MCEF-1.11 in the package
And I tried to use MCEF-1.31, it is white again
It's so weird

Okay,it caused by JCEF. Put the complete JCEF into .minecraft/jcef and it works well
Thank you these days!!!