This WYSIWYG (What You See Is What You Get) program generates HTML and JavaScript code to open a URL in a new (PopUp) window. You can specify the properties of the new window, including its size, attributes (whether it is resizable, has a menu bar, and so on), and name. For example, you can use it to open a larger image in a separate window when the visitor clicks a thumbnail image; with Yaldex PopUp you can make the new window with exact size of the image.

If you specify no attributes for the window, it opens at the size and with the attributes of the window that opened it. Specifying any attribute for the window automatically turns off all other attributes that are not explicitly turned on. For example, if you set no attributes for the window, it might open at 640 x 480 pixels and have a navigation bar, location toolbar, status bar, and menu bar. If you explicitly set the width to 640 and the height to 480 and set no other attributes, the window opens at 640 x 480 pixels and has no navigation bar, no location toolbar, no status bar, no menu bar, no resize handles, and no scroll bars.