read value from textbox and 7 segment LED display this value

when I enter value in textbox, 7 segment LED will display it how to conver string to value so 7 segment LED display this value EX: enter 12 then 7 segment LED display 12 I use Arduino uno and Arduino ethernet shield w5100

when I enter value in textbox, 7 segment LED will display it how to conver string to value so 7 segment LED display this value EX: enter 12 then 7 segment LED display 12 I use Arduino uno and Arduino ethernet shield w5100