Trigger Captive Network Assistant on Raspberry Pi

I have a Raspberry Pi which currently broadcasts a wireless access point via an Edimax USB adapter. I'm able to successfully connect to the access point and browse a locally hosted web page which is forced for all WiFi clients. I'm using isc-dhcp-server, dnsmasq and hostapd to accomplish this. I will like to push this a step further by automatically launching a browser like captive portals do at public hotspots and coffee shops. Upon successful connection to the WiFi network, I need the locally hosted page to pop-up on iPhones, Androids, and computers. I've read that I need to deliver a wispr response of some sorts, or block traffic to test pages built into the operating systems. All traffic is already redirected to the local page using dnsmasq so I'm not sure why this isn't working.