Dropdown to populate textbox with multiple selections
I'm doing a simple form for a process at work and thought it should be really simple. I placed a list-box on the form so as users could make multiple selections (Ctrl+click). Now the business unit has come back saying they want to swap the list box for a drop-down list, and have the drop-down populate a text box with multiple selections (on change or click). I'm not a coder and have looked for something similar but haven't been too lucky in my search.
I picked up the piece of code below which populates the text box, but it always replacs the first seletion with a different selection. Can anyone please help modify this code so it adds mutiple choices to the text box.