david77

If I get my on-screen processor working, can I then get it to access the traffic lights page? I had 2 processors, and 8-bit one based on the Z80 and a 16-bit RSIC processor running ARM's Thumb code. I also had a BASIC interpreter. Any of those could drive any one of half-a-dozen models, so I'd like to keep the pages separate and have an include or uses line somewhere. Can you please tell me how to do it? Thanks

Thanks for pointing me to the error console. I've never found it before and I wrote my first web pages over 15 years ago. My traffic lights work http://homepage.ntlworld.com/stonebanks/traffic9.svg so now I will try to get the on-screen microprocessor working.

It looks as tho http://www.w3.org/Graphics/SVG/IG/resources/svgprimer.html#interactivity provides the answer to my query.<script><![CDATA[function changeFill(){C=document.getElementById("C")C.setAttributeNS(null,"fill","black")}]]></script><circle id="C" cx="80" cy="100" r="22"fill="grey" onclick="changeFill()"/></svg> Thanks for advice.

Thanks - when I have had trouble in the past, I have enabled error reporting in IE and then used the Microsoft debugger - but IE doesn't work with SVG. I have now found the error console in Opera that I have been using - but there is masses if info from pages that have been run. I must find out how to clear it so that I can see new info for my page. Thanks again

Check your error console, there are syntax errors in the turn_on and turn_off functions. You have the parameters quoted so that they're strings instead of identifiers. There are some links in my signature about the various error consoles in browsers.

Thanks but - where is a link to "my signature" and what's an "error console"? I don't know what I am doing. All I want to do is change the fill color of a circle, initially just to get me going, from a button click. I don't care whether I use SVG or Canvas for the graphics. I looked at Raphael - that shows me how to draw a circle but I couldn't see how to define the fill color. I have done a fair amount of javascript programming - my CGT calculator runs to over 1,000 lines of code, but this is my first attempt at graphics. I would put up with it running on only one browser - I'll worry about other browsers once I get something working.

When I was teaching 25 years ago, I wrote a program in Turbo Pascal to represent an on-screen microprocessor so that students could see their programs working. I also wrote progs for models for student exercises. Now that I am retired, I would like to get these working on the web. So far I have traffic3.htm at http://homepage.ntlworld.com/stonebanks/traffic3.htm using svg graphics and traffic5.htm at http://homepage.ntlworld.com/stonebanks/traffic5.htm using canvas -see http://homepage.ntlworld.com/stonebanks/modelinfo.htm I have added a button to control the lights - but it doesn't work. I would appreciate any advice persuading javascript to control these lights. Thanks