How to get the click event on next button
 

When I use nsis to make a install file. I have a custom page with two radio button, But when i click the next button, it takes no effects. Below the code

page custom HaveInstall EndHaveInstall

Function HaveInstall
;mycode no error
FunctionEnd

Function EndHaveInstall
ReadINIStr $0 "$PLUGINSDIR\uninstall.ini" "Field 3" "State"
Strcmp $0 1 change3
ReadINIStr $0 "$PLUGINSDIR\uninstall.ini" "Field 4" "State"
Strcmp $0 1 chage4
GetDlgItem $0 $HWNDPARENT 1
Strcmp $0 0 0 nextpage
Abort
change3:
WriteINIStr "$PLUGINSDIR\uninstall.ini" "Field 4" "State" 0
Abort
chage4:
WriteINIStr "$PLUGINSDIR\uninstall.ini" "Field 3" "State" 0
Abort
nextpage:
Strcmp $isinstalled 1 0 +9
ReadINIStr $0 "$PLUGINSDIR\uninstall.ini" "Field 3" "State"
Strcmp "1" $0 0 +3
Strcpy $isupdate "1"
Goto +4
ReadINIStr $0 "$PLUGINSDIR\uninstall.ini" "Field 4" "State"
Strcmp "1" $0 0 +2
Strcpy $isupdate "0"
Call ProcessInstall
FunctionEnd

when i click the next button, I will not take effect, so one who know it please help me

How can I check the change that user click the next button

So now I will close the thread with the code
ReadINIStr $0 "$PLUGINSDIR\uninstall.ini" "Settings" "State"
StrCmp $0 0 nextpage