Displaying outdated JavaScript in modern browsers

[Adlago]

To increase site performance, and to improve loading speed, I think it's time to remove java script codes used in obsolete browsers.
Here is an example from a test - removing these obsolete java scripts will reduce the volume by about 11 kbps. or this will shorten the java script download time by about 150 ms

[Rikki]

Those files aren't obsolete - they are the foundation of our framework. What your tool is finding is polyfills for old browsers that libraries we use (such as jQuery) include. 

[Adlago]

11 minutes ago, Rikki said:

Those files aren't obsolete - they are the foundation of our framework. What your tool is finding is polyfills for old browsers that libraries we use (such as jQuery) include. 

These results appear only in a mobile performance test. Is there a way to reduce javascript for mobile browsers?

[bfarber]

We do not deliver different output based on the user agent - we deliver the same output and use responsive design principles to adjust the interface.

[13.]

You (IPS) can load polyfills only when they are needed and don't waste the traffic for the majority of browsers.

[Rikki]

3 hours ago, Mr 13 said:

You (IPS) can load polyfills only when they are needed and don't waste the traffic for the majority of browsers.

We don't load (many) polyfills ourselves - they are included with libraries that we use. Those libraries will only execute them when needed, but the code is still sent to the browser since we bundle and minify javascript.