Browsers are under siege now and can be hijacked by going to a bad site. Most of the time I can reset the browser and clear up the simpler browser hijacks.
For phones, it depends on the hijack. Some can be so invasive folk have to buy a new phone since, well, you can read it in a link to follow.
Just like a PC we always backup our stuff on the phone today. For simple phone infections a reset or a reset that clears everything is done. But there's a new nasty out there that the owner helps install. You can read about it at http://arstechnica.com/security/2015/11/new-type-of-auto-rooting-android-adware-is-nearly-impossible-to-remove/
I am new to this group and have never really posted anything before in any forum. My cell phone started acting funny a week ago. I texted my nephew my new cellphone number and he got a bizarre message and his phone started acting up then my Home PC said that my browser was compromised. Is it possible for both my cellphone and my computer to be hacked at the same time? Anyone?