Web Browser Drop Down Menu Automation

I have a need for some sort of utility to manipulate drop down menus on a web page. There are 3 drop down menus currently & I need something that will sequentially go through all the variations. So the utility needs to be able to find them, figure out what's in them & then go through all the variations. After each individual variation an "Entry" is needed to input each variation, although this isn't absolutely necessary (like if it makes it too expensive to program). If it can't automatically find them then it should be able to be pointed to the drop down menu & be able to blindly go through the combinations if it can't fathom the contents. The steps for each variation should either be autmatically run, ie., variation 1: Enter. Variation 2: Enter etc etc. Or they should be stepable with the space bar of the PC keyboard, this being set with something like "Auto Step/ Yes/No". We may need the ability to have the "Entry" configurable to get the web page back to the ordering point. Currently a web browser "Back" command would do the job. The ability to automate a Left Mouse Button click would also be needed & configurable as On/Off. There also needs to be a "Stop" function so if we see an error we can get on it right away (see below). The utility should also be able to cope with different numbers of drop down menus, like 5, 10 & so on, should the web page change. This should be a configurable variable somewhere, it doesn't need to be something it works out fo itself if it is going to be too difficult to program. A "Tab" keystroke would initiate the first drop down menu on the page so this needs to be included & configurable with an "On/Off". This is for testing out some problems with a website selling footwear & other articles with customer selectable attribtes. Some color/size combinations aren't coming through as orders & are getting lost. I've tried to test it out, but my fingers are getting sore! (total of 35,000 possible variations across our whole range). The drop down menus have different contents, some alpha some numnerica. ie., Sizes drop down menus may run from 5 to 12 (in whole sizes) while another may be for Sizes from 5 to 13.5 (in half sizes), while others may contan Colors red, white, black etc etc or Sizes X Small, Small... Large... XX Large. The actual pages aren't available to the public (they only run on a local machine at present) until the bug is fixed as it is causing too much trouble with our customers. Sorry, we can't give you access to this machine as it is tightly quarantined. If you need any more info or if any of this does't make sense please let us know & we'll try our best to assist you. Finally the instructions for use really do have to be "John & Janet do programming". Keep it clear & easy, please, we're not as smart as you!