javascript window open( )

A potential problem with subwindows is that they can be buried under the main window if the user clicks on the main window (or a script gives it focus). Any script that opens a subwindow should also include a focus( ) method for the subwindow (in Navigator 3 and later, and in IE 4 and later) to make sure it comes to the front in case it is already open. Subsequent invocations of the window.open( ) method in which the windowName parameter is the same as an earlier call automatically address the previously opened window, even if it is underneath the main window (and thus without bringing the window to the front).

The optional third parameter gives you control over various physical attributes of the subwindow. The windowFeatures parameter is a single string consisting of a comma-delimited list (without spaces between items) of attribute/value pairs:

newWindow = window.open("someDoc.html","subWind",
"status,menubar,height=400,width=300");
newWindow.focus( );

By default, all window attributes are turned on and the subwindow opens to the same size that the browser would use to open a new window from the File menu. But if your script specifies even one attribute, all settings are turned off. Therefore, use the windowFeatures parameter to specify those features that you want turned on.

If you encounter problems referencing a subwindow immediately after it is created, the problem is most likely a timing issue (affecting IE for Windows more than others). Script statements seem to want to reference the window before it exists completely. To work around the problem, place the code that works with the subwindow in a separate function, and invoke that function via the setTimeout( ) method, usually with no more than 50 milliseconds needed.

Managing multiple windows through scripts can be difficult. Security restrictions across domains frequently foil the best intentions. Users aren't always fond of windows appearing and hiding on their own. If your audience uses newer browsers, consider simulating windows with positioned elements.

• A complete or relative URL as a string. If an empty string, no document loads into the window.
• An identifier for the window to be used by target attributes. This is different from the title attribute of the document that loads into the window.
• A string of comma-delimited features to be turned on in the new window. Do not put spaces after the comma delimiters. The list of possible features is long, but a number of them are specific to Navigator 4 or later and require signed scripts because they are potentially a privacy and security concern to unsuspecting users. The features are listed as follows. To turn on a window feature, simply include its case-insensitive name in the comma-separated list. Only attributes specifying dimensions require values be assigned.

• Boolean value (for IE only) that controls the effect of the new window's URL on the global history of the browser. Set to true to replace the current page with the new window's URL (so that the current page won't be accessed through the Back button); set to false to add the new window's URL to the history, as normal.

Window object reference.