1, can not surf the internet to see if the computer can be online, this can check your router oh.
2, if only the iphone is not online, we can reconnect to the WiFi network to try
3, restart your iphone, most of the minor problems, you can try to shutdown and restart the device
4, if still unable to resolve, you can click on the iphone Home screen "Settings"
5, find "General"
6, find "General" at the bottom of the "restore"
7, select "Restore Network Settings", confirm restore, the phone will restart, the network settings will return to just buy a mobile phone when, note that other software, mobile phone storage files are still in, but the phone network restore
8, and then reconnect the WiFi, enter a password to see if the resolution
If the above method is still unable to solve your problem, we can try to modify DNS to resolve, the specific procedures
1, open the "Settings" application.
2, click on "Wireless LAN" into the Wi-Fi list, and select the available Wi-Fi network connection.
3, connect the available Wi-Fi network, and then click the Wi-Fi network name to the right of the "Display Information" button (letter "i").
4. Scroll down the details section of the Wi-Fi network to find the "dns" option section.
5, Next on the keyboard that pops up you need to change the DNS value. In this example we use the 8.8.8.8 provided by Google.
6, click on the top left corner of the page "wi-fi" button, you can exit the DNS settings.
Note: DNS we can set is 8.8.8.8 or 114.114.114.114 this can be, if not, you can ask your local ISP to see how much DNS.