Lynx invokes a built-in Line Editor for entering strings in response
  to prompts, in forms, and for email messages if an external
  editor has not been defined. Additional alternative key-bindings
  can be offered by configuring with
  --enable-alt-bindings or by adding them in
  LYEditmap.c before compiling Lynx. If available,
  they may be selected via the “o”ptions menu, or by
  editing lineedit_mode in the “.lynxrc” file.
Note: setting emacs/vi keys ON has no direct effect on line-editor bindings.
This is the Alternative Binding keymap.
     ENTER  Input complete        -  RETURN
     TAB    Input complete        -  TAB, Do
     ABORT  Input cancelled       -  Ctrl-G, Ctrl-O, (Ctrl-C on some systems)
     ERASE  Erase the line        -  Ctrl-U
     BACK   Cursor back     char  -  Left-Arrow,  Ctrl-B
     FORW   Cursor forward  char  -  Right-Arrow, Ctrl-F
     BACKW  Cursor back     word  -  Ctrl-P
     FORWW  Cursor forward  word  -  Ctrl-N
     BOL    Go to begin of  line  -  Ctrl-A, Home, Find
     EOL    Go to end   of  line  -  Ctrl-E, End,  Select
     DELP   Delete prev     char  -  Backspace, Delete, Remove
     DELN   Delete next     char  -  Ctrl-D (see note 1)
     DELPW  Delete prev     word  -  Ctrl-R
     DELNW  Delete next     word  -  Ctrl-T
     DELEL  Delete to end of line -  Ctrl-K
     UPPER  Upper case the line   -  Ctrl-^
     LOWER  Lower case the line   -  Ctrl-_
     LKCMD  Invoke cmd prompt     -  Ctrl-V (in form text fields, only) (see note 2)
Special commands for use only in textarea fields (see note 3):
          Textarea external edit  - Ctrl-X e
          Insert file in textarea - Ctrl-X i
          Grow textarea           - Ctrl-X g
  
    TPOS    Transpose characters                   -  Ctrl-t
    SETMARK Set mark at current position in line   -  Ctrl-@
    XPMARK  Exchange current position with mark    -  Ctrl-x Ctrl-x
    KILLREG Kill region between mark and position  -  Ctrl-x Ctrl-w (see note 3)
    YANK    Insert text last killed (with KILLREG) -  Ctrl-y
  Here is a little textarea for practice:
See the Lynx Line Editor page for an explanation of terminology and key-names.