The following is a passage taken from the "Hand-Book of Anglo-Saxon and Early English" by Hiram Corson, published 1873. [page 3 of JOHN I ] It shows the word for JOHN as used in the Anglo-Saxon.
In the middle of the figure is the word "Iohanne". It is similar to the Greek spelling, and becomes the word JOHN in the English.
The front page of the Anglo-Saxon reference is shown: