Hi All, I am using IE11. I want to change the compatibility mod

This looks more like a question suitable for a JavaScript Forum more than for Appian Forum, you may want to ask this in a different place for more suggestions.

The way a webpage can be forced to be rendered in compatibility mode is through the <meta> tag and its content="IE=Emulate*" attribute which you could change with JavaScript, however, since Appian uses frames in some parts of the application you could be modifying only the current nested frame which would result in the parent frame having a different <meta> tag which is not a valid declaration for IE meaning the compatibility mode will be ignored.

If the concern is Appian's compatibility then you shouldn't be concerned; Appian is compatible with IE 11 forum.appian.com/.../System_Requirements on the other hand if your concern is your custom JavaScript you better add the logic to handle other versions of IE to your own code.

Some useful links

gist.github.com/.../5733469
stackoverflow.com/.../how-to-turn-on-ie9-compatibility-view-programmatically-in-javascript