jQuery plugin to detect caret position within a text input. And method to get the current word at caret position.

caret-position.jquery.js

/**
 * jQuery Plugin to get cursor position
 */
(function ($) {
    $.fn.getCursorPosition = function () {
        var input = this.get(0);
        if (!input) return; // No (input) element found
        if ('selectionStart' in input) {
            // Standard-compliant browsers
            return input.selectionStart;
        } else if (document.selection) {
            // IE
            input.focus();
            var sel = document.selection.createRange();
            var selLen = document.selection.createRange().text.length;
            sel.moveStart('character', -input.value.length);
            return sel.text.length - selLen;
        }
    }
})(jQuery);

wordAtCaret.js

// Important, inputBar is a jQuery selector of a <input type="text" />
// Checks where the caret is and collect the word surrounding the caret
function getCurrentWordAtCursorPosition(inputBar) {
    var cursorPosition      = actionBar.getCursorPosition(),
    	leftWordBoundary    = cursorPosition,
    	rightwordBoundary   = cursorPosition,
    	command             = inputBar.val(),
    	wordpattern         = /\w/, // no digits, no dash, unused, here for the taking
	    recognizerPattern   = /(\w|\d|-|#+)/,
	    currentPattern = recognizerPattern;

    // TODO: This case covers the case where the caret is "after" the word
    // It won't cover the case where the caret is "before" the word
    if(command.charAt(leftWordBoundary).match(/\b|\w/) || command.charAt(leftWordBoundary) == "") {
        leftWordBoundary--;
    }
    while(command.charAt(leftWordBoundary).match(currentPattern)) {
       leftWordBoundary--;
    }

//    if(command.charAt(leftWordBoundary).match(/\b/)){
//
//    }
    while(command.charAt(rightwordBoundary).match(currentPattern)) {
       rightwordBoundary++;
    }

    return command.slice(leftWordBoundary+1,rightwordBoundary);
}