javascript - Navigate to next text element with keyboard arrow when at start or end of text -

i having hard time navigating 1 element using keyboard arrow; want navigation occur when cursor @ start or end of text i.e. "move right if @ end of text , move left @ start of text, press left arrow when @ end of text not want navigate, want let default event happen."

here's start of want, try1

this function need writing

function isendorstartoftext($this) {     return true;     // @todo calculate here }   

you want separate 2 checks because can @ end of string , press left, shouldn't focus previous field.

in modern browsers can node.selectionstart on node, check on left-key press if selection start 0:

if ($this[0].selectionstart === 0) {     e.preventdefault();     if ($('#'+previous_id).length > 0) {         $('#'+previous_id).focus();     } } 

for right key, check:

if ($this[0].selectionstart === $this.val().length) {     e.preventdefault();     if ($('#'+next_id).length > 0) {         $('#'+next_id).focus();     } } 

i updated example: http://jsfiddle.net/88vl8/7/ (tested in chrome)

ps: code not work on ie, there's polyfill available here on stackoverflow, search "how caret position in textarea?"