Netscape Navigator 4.06 and 4.5 changed the behavior of the JavaScript console. In previous versions, when you type javascript: in the URL field, your window transforms into a JavaScript console. The output of the JavaScript console is printed in this window while errors are printed in an alert box, one box per error. In Navigator 4.06 and 4.5, when you type javascript: in the URL field, a new window pops up with a javascript typein entry box, and buttons to clear the console and close it.

The dialog window in earlier versions became annoying to most people, especially for those users who did not find the messages that helpful. In Navigator 4.06 and 4.5, you can direct the HTML page errors to the JavaScript console. Since the console is normally hidden, errors are hidden as well from the user, unless he or she opens the console. You can set a preference to automatically open the console when a JavaScript error occurs. The error message is the same, whether it is displayed in a popup window or the JavaScript console, and looks like:

JavaScript Error: file:/D|/Yehuda/Column26/code7.html, line 11:

syntax error. 

c <> b.length;
...^

Currently, JavaScript errors are printed in English. International versions will be supported in the future.

You can set the JavaScript console's preferences in the JavaScript preference file, prefs.js, under <Netscape Path>\Users\<user name>. Automating the opening of the JavaScript console can be done by inserting the following line to the above file:

user_pref("javascript.console.open_on_error", true);

You can revert back to the dialog box for error display, by inserting the following line in the JavaScript preference file:

user_pref("javascript.classic.error_alerts", true);