• makeLinkedImage(): creates the linked image of the watermark.
• doThisCommandEveryIntervalMS: calls waterMark() repeatedly to check for changes in the window's or scroll area's size.

docjslib_setPosFromTop("docjslib", windowHeight + pageScrollTop - 
                            (imageHeight + bottomSpacer));
docjslib_setPosFromLeft("docjslib", windowWidth + pageScrollLeft - 
                            (imageWidth + rightSpacer));
var topZ = docjslib_findHighestZ();
docjslib_setZposition("docjslib", topZ);

Notice how the position of the top left corner of the image is computed. It depends on the window size (windowHeight and windowWidth), how much is the page scrolled (pageScrollTop and pageScrollLeft), a spacer between the image and the window (bottomSpacer and rightSpacer), and the size of the image, imageHeight and imageWidth).

Also, notice that the highest Z index is computed on every iteration, as Z index of elements can change via the setZposition() function of DOCJSLIB.

Learn more about our page watermarks and DOCJSLIB in Column 29, DOCJSLIB Version 3.0: Supporting Watermarks, and Column 33 DOCJSLIB Version 4.0: Scrollers, Watermarks, and Games.

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