Interface for a chemical speciation program

Project Description:
We need a web interface (sketch at https://docs.google.com/folder/d/0Bz0Ix7hc9o8jc3NvSzZQTVIzSU0/edit?usp=sharing&docId=1xZZ9qnxjsMACaMQw_cl3Ds18Q0-yEAHqSPvI2bDTrtg ) that allows the user to:
1. define species characterized by a string, an integer, and an interval of real numbers
2. drag and drop the species to combine them and define the plot to be output
3. pass the input to a script that calculates the plot (a java function for computing each point of the plot will be provided).
Code must be open.