In DFP I'm able to set line item and key value pair to target bidders and price. In *prebid.js* how do I send floor price dynamically to each bidders while sending request?

I have searched in prebid site's and got one function `pbjs.adserverTargeting()` which returns following details during response:

> 
> { "hb\_bidder": "appnexus",
>  "hb\_adid": "7a53a9d3",
>  "hb\_pb: 1.0" }
> 
> 
> 

Here `hb_pb` means floor price? If yes how can I sent those details during request?