The demo is about multilevel menu linkage.The Chinese city is the example of my demo.The 1st input can be select provience,when you select one,the provience's name will show in the 3rd input.Then the 2nd input can be select city whose provience has been selected at first,when you select the city,you can see the city's name will show in the 3rd input after the porvience.By the way you can change something to fit your project.