Common Web Site Error Messages

Error: dclkpuwin has no properties

DoubleClick pop under advertisement windows typically are created by JavaScript code inserted into the body of a web page just before the ending BODY tag. The code looks very similar to:

dclkpuwin = window.open('http://ad.doubleclick.net/...','...');
document.onload = dclkpuwin;

//Blur the window
dclkpuwin.blur();

In Mozilla, and Internet Explorer on Windows XP SP2, a blocked request to open a window will return a null value. This means that the variable dclkpuwin (cute name, eh?) is null and any request to access properties or methods on the window object will fail.

Of course, this code could have been written to take blocked pop under windows into account, but I will leave that as an exercise for the reader.

Error: document.all has no properties

Many sites do not support alternative browsers due to the use of proprietary, non-standard properties in Internet Explorer.

document.all is a non-standard property which is used to obtain references to elements in a web page using their ID attributes. The appropriate, modern, standards-based approach is to use document.getElementById. See Marcio Galli's DevEdge article Updating DHTML Web Pages for next generation browsers: for more information on how to code for modern browsers.