I am trying to show the GLTF on the Model-Viewer. I want to enable the Double-Sided option in the code.

Hello Everyone i am trying to show the Gltf on the Model-Viewer i want to enable the Double-Sided option in the code Actually the Issue is the GLTF which i a, showing in my Website is not appering correctly but when i got the Model-viewer and in the edit section when i enable the Double-sided the Model is Getting Visible correctly i thought my model must be having some issue byt when i check the model on the online 3d model the model was correct the issue was of the Model-viewer and i am not able to correct that via code Please Somebody help me out