One option is to force the web browser component to run in a different mode than IE 7 compatibility mode by setting a registry key on the PC which runs the Spotfire Professional client. In the Windows registry, you would add a DWORD entry with the key "Spotfire.Dxp.exe" to:
HKEY_LOCAL_MACHINE (or HKEY_CURRENT_USER)\Software\Microsoft\Internet Explorer\Main\FeatureControl\FEATURE_BROWSER_EMULATION . Set it to 11000 for IE 11 (or 10000 if IE 10 is installed in the host computer).
For more details on this value, refer to https://msdn.microsoft.com/en-us/library/ee330730(v=vs.85).aspx#browser_emulation. Note that this is only a workaround, and it is not officially supported. In some cases it might cause an unexpected behavior in other parts of the application that use the web browser component. Another option is to engage TIBCO Spotfire Professional Services to make the JavaScript code support IE 7.