It´s strange that http://www.firstpersontetris.com/ and http://oos.moxiecode.com/js_webgl/xwing/ that uses webgl works in my Firefox.
When I put "about:support" in firefox, it shows me these data:
Data do driver 10-1-2013
Data do driver (GPU #2) 11-12-2014
Descrição do adaptador Intel(R) HD Graphics Family
Descrição do adaptador (GPU #2) NVIDIA GeForce GT 750M
Deslocamento/Zoom assÃncrono none
Direct2D ativo true
DirectWrite ativo true (6.3.9600.17795)
Drivers do adaptador igdumdim64 igd10iumd64 igd10iumd64 igdumdim32 igd10iumd32 igd10iumd32
Drivers do adaptador (GPU #2) nvd3dumx,nvwgf2umx,nvwgf2umx nvd3dum,nvwgf2um,nvwgf2um
GPU #2 ativa false
ID do dispositivo 0x0a16
ID do dispositivo (GPU #2) 0x0fe4
ID do fornecedor 0x8086
ID do fornecedor (GPU #2) 0x10de
Janelas aceleradas pela GPU 1/1 Direct3D 11 (OMTC)
RAM do adaptador Unknown
RAM do adaptador (GPU #2) 2048
Renderização WebGL Google Inc. -- ANGLE (Intel(R) HD Graphics Family Direct3D11 vs_5_0 ps_5_0)
Subsys ID 05f61028
Subsys ID (GPU #2) 05f61028
Versão do driver 10.18.10.3316
Versão do driver (GPU #2) 9.18.13.4475
windowLayerManagerRemote true
AzureCanvasBackend direct2d 1.1
AzureContentBackend direct2d 1.1
AzureFallbackCanvasBackend cairo
AzureSkiaAccelerated 0