I have a wireless heart rate monitor for my new cross trainer. Is it possible that I can some how use the same heart rate strap to monitor my heart rate through my phone web I’m out riding?

I don’t know how the HR strap communicates with my cross trainer?

What make it is? If it’s ant+ compatible you can get a little dongle thing that you plug into the iPhone that will link up with it. I think it’s by wahoo.

Or if its a Bluetooth heart rate monitor, you can just connect it to the iPhone, no dongle required.
If its Bluetooth Smart (aka Bluetooth Low Energy), then it won’t work unless you have an iPhone 4S or 5.

Garmin make (?made) an ANT+ dongle too, but it needs a 30-pin dock connector so doesn’t work with anything newer than a 4S.

Irritatingly, IIRC Polar have their own, proprietary standard so I don’t know if there’s a way of linking their stuff to an iPhone. When I used to go to the gym, the machines there would talk to Polar gear but no-one else’s.