Hello all, I've got a requirement to write a script that checks some condition on the server, and to display one image if the condition is true, another if the condition is false. But I want to update the image every time the condition changes.
For now, I'm using a META REFRESH tag so that the CGI script is rerun every 30 seconds. But this is not a very good solution, as the whole web page gets redrawn even when nothing has changed. I've also thought about using frames, and having one frame that repeatedly refreshes while the rest of the page stays static. Again, not a very elegant solution. Is there some way (perhaps using JavaScript in conjunction with CGI) to query the server periodically, and only update the image when the condition changes? Here's the relevant excerpt from my code: ##################################### $GoNogo = "go"; # or "stop" depending on server-side condition print <<'End of Header'; Content-type: text/html <html> <head> <title>My title here</title> <meta http-equiv="Content-Type" content="text/html; charset=iso-8859-1"> <meta http-equiv="Refresh" content="30"> End of Header # irrelevant code here print <<"End of Javascript"; <script language="javascript" type="text/javascript"> function setStatus() { if ("$GoNogo" != "go") { document.fgColor = "#660000"; document.TheImg.src="go.gif"; document.links[0].href="#"; } else { document.fgColor = "#006600"; document.TheImg.src="stop.gif"; document.links[0].href=$launchUrl; } } // --> </script> </head> End of Javascript # irrelevant code here print <<'End of Body'; <body onLoad="setStatus()"> Top of page here <center> <a href="#"><img name="TheImg" ></a> </center> More body text here </body> </html> End of Body ############################################ Thanks in advance for any help! Jim Bander, Ph.D. Operations Research Specialist Norfolk Southern Corporation One Georgia Center 600 W Peachtree St, NW, Suite 900 Atlanta, GA 30308 Phone: 404 897-3060 Fax: 404 897-3063 e-mail: [EMAIL PROTECTED] -- To unsubscribe, e-mail: [EMAIL PROTECTED] For additional commands, e-mail: [EMAIL PROTECTED]