JavaScript Bible, Gold Edition part 139. This book will bring programmers and non-technical professionals, including casual programmers and scripters, painlessly up to speed on all aspects of mastering JavaScript. Key topics include programming fundamentals, JavaScript language elements and how to use them effectively, and how to easily and efficiently add powerful new functionality to HTML documents and Java applets. | 1228 Part V Putting JavaScript to Work you include these attributes without fail throughout your HTML documents you won t be plagued by intermittent behavior. Scripts not working in tables Tables have been a problem for scripts through NN3. The browser has difficulty when a SCRIPT tag is included inside a TD tag pair for a table cell. The workaround for this is to put the SCRIPT tag outside the table cell tag and use to generate the TD tag and its contents. I usually go one step further and use to generate the entire table s HTML. This step is necessary only when executable statements are needed in cells for example to generate content for the cell . If a cell contains a form element whose event handler calls a function you don t have to worry about this problem. Timing problems One problem category that is very difficult to diagnose is the so-called timing problem. There are no hard-and-fast rules that govern when you are going to experience such a problem. Very experienced scripters develop an instinct about when timing is causing a problem that has no other explanation. A timing problem usually means that one or more script statements are executing before the complete action of an earlier statement has finished its task. JavaScript runs within a single thread inside the browser meaning that only one statement can run at a time. But there are times when a statement invokes some browser service that operates in its own thread and therefore doesn t necessarily finish before the next JavaScript statement runs. If the next JavaScript statement relies on the previous statement s entire task having been completed the script statement appears to fail even though it actually runs as it should. These problems crop up when scripts work with another browser window and especially in IE for Windows ironic in a way . In discussions in this book about form field validation for example I recommend that after an instructive alert dialog box notifies
