Need some Specific mods to some existing PHP code and tutorial for developing more

A previous VWorker developed some PHP Code. I'm a VB programmer, not PHP. I've attached a new PHP project using his original PHP project as an example. Some questions I have include: Background: For this project, I don't have a global Metric vs English units. People would want to do this calculation with a mix of units for various inputs. The questions I have include: 1) How to make the metric/english combo box Visible = False, or if that is even possible? 2) It appears that the text for the Combo boxes must not include spaces. Does that seem correct? 3) If we change a combo box setting, can we instantly change the text in a label? For example, if we change the "Units" choice for a particular text box, can we change the Label for that text box to reflect the changed units? 4) I've never had the time to pursue the Netbeans environment like I had hoped. Could you just explain how you debug your php code on your computer using notepad and then running it in IE locally on my computer to debug, or however you would suggest to do it?