Removing part of code from JS
I get the script content and in it i have sometimes this:

    if(!plugin) {
      if((navigator.userAgent && navigator.userAgent.indexOf("MSIE")>=0)&&((navigator.userAgent.indexOf("Windows 95")>=0)||(navigator.userAgent.indexOf("Windows 98")>=0)||(navigator.userAgent.indexOf("Windows NT")>=0))) {
       
      }
    }

So, I want to remove this `if(!plugin)` and everything inside this `if` and than to append my new script. Is it possible?
Removing part of code from JS
===

I get the script content and in it i have sometimes this:

    if(!plugin) {
      if((navigator.userAgent && navigator.userAgent.indexOf("MSIE")>=0)&&((navigator.userAgent.indexOf("Windows 95")>=0)||(navigator.userAgent.indexOf("Windows 98")>=0)||(navigator.userAgent.indexOf("Windows NT")>=0))) {
       
      }
    }

So, I want to remove this `if(!plugin)` and everything inside this `if` and than to append my new script. Is it possible?