There is another way to search the City Directories, and other large databases with many pages. The user can do a Browse and Search technique. Let me demonstrate it for you.
I was looking for all of the McKnew entries in the San Francisco City Directories. My preference is to start with the first directory and work through to the last one, writing down all of the entries so that I can construct a history of the surname in the city. Here is the home page screen for Footnote.com:
Do you see the "Browse Titles" link just below the row of "Historical Era" links, and just above the "Popular this week" line? If you click on the "Browse Titles" link, you get this page that can list all of the titles by collection:
In the screen above, I clicked on "News and Town Records" link in the left-hand column, then on the "City Directories" link in the second column, then on the "California" link in the third column, and the list of cities appeared in the fourth column. I clicked on "San Francisco" and the table moved a column to the left, then selected a year from the column of years (I chose 1887 for some reason) and the list of pages appeared in the right column (two screens that overlap):
I received one match for "McKnew" in this specific directory. When I clicked on the "View Image" link, the image came up:
This image was on page 824 of the 1,390 page San Francisco City Directory for 1887. If the entries for a surname are on more than one page, the user can click on the previous or next page of the filmstrip at the bottom of the page.