Stop Google Chrome Loading A Frame Before It's Ready?

I have a website which includes stories with multiple chapters. These chapters have a set of clickable arrows at top and bottom to take you forwards and back through the chapters, including a "last chapter" arrow.When a story is in progress, the URL of the last chapter changes with each chapter added. Rather than having to go back into every previous chapter and change the URL of the last chapter by hand, I set them up so that the "last chapter" arrow is actually in an inline frame. That way, I only have to change the URL once, in the file go_end.htm which is the source for the frame. So both the picture of the arrow and its hyperlink are being accessed from outside.

My web pages are also set up to run on all major browsers and to detect the window width and resize all the artwork to fit, regardless of the browser and whether or not it accepts percentage sizes. Go_end.htm is no exception - it contains Javascript code which resizes the arrow so it is the same size as the ones which are actually in the parent page, outside the frame.This setup works perfectly in IE and Netscape, but Google Chrome either fails to display the arrow or makes it huge so it doesn't fit the frame. This seems to be because their superfast new Javascript editor is *too* fast. If I bung an alert command into go_end.htm, asking it to say the value of picWidth (the variable which sets the width of the arrow) as it loadfs, what happens is this.

Google Chrome displays an alert saying that picWidth is zero, then loads the first instance of the inline frame with no got-to-end arrow. Then it displays an alert giving a proper value for picWidth and loads the second inline frame with the arrow correctly displayed and sized. If I take out the alerts, it doesn't load the arrow in *either* frame. It's obvious that inserting the alert command somehow forces it to recognise the value of the variable which it then retains for long enough to load the arrow on the second pass.Any ideas for some command other than alert which would trick it into not loading the image until it's recognised the variable? If I put a time delay on loading the frame I can't see that that would help - the problem is that from the point at which it starts actually loading the frame it needs to wait for the variable to be set.