found my solution:
Please mind that this steps is a manual step for adding plugin to cordova (the common step will be installing cordova on your machine and then install the plugins)

just open
Xcode -> click the folder icon -> resources -> config.xml

inside the plugins tag add the following line:
<plugin name="InAppBrowser" value="CDVInAppBrowser" />
save it and in your app you can just:"", "_system"); //second parameter tell phonegap to open the url on device browser

3 values for the second parameter and its explanation:
  • _self - opens in the Cordova WebView if url is in the white-list, else it opens in the InAppBrowser
  • _blank - always open in the InAppBrowser
  • _system - always open in the system web browser
full explanation: search for "_system" or ""