1. A method for creating a job control language (JCL) card, the method comprising: obtaining JCL function choices and parameters associated with the JCL function choices from a storage device of a computer, wherein the JCL function choices are functions associated with an EXEC line of the JCL card; transmitting for display the JCL function choices to a graphical user interface (GUI) of the computer; receiving a function choice selection in response to a user interacting with the GUI to specify a job; customizing, by the computer, a panel for display based on the received function choice selection and the parameters associated with the received function choice selection; transmitting for display the customized panel to the GUI; receiving values for at least a subset of the parameters associated with the received function choice selection via the user interacting with the GUI; mapping, by the computer, the received function choice selection and received values to an associated JCL command, wherein the mapping includes context and syntax required by the JCL command; creating, by the computer, the JCL card that instructs a mainframe computer to execute the specified job based on the mapping; and executing the JCL card by the mainframe computer.