获取input中的光标位置

(function($, undefined) {

    $.fn.getCursorPosition = function() {

        var el = $(this).get(0);

        var pos = 0;

        if ('selectionStart' in el) {

            pos = el.selectionStart;

        } else if ('selection' in document) {

            el.focus();

            var Sel = document.selection.createRange();

            var SelLength = document.selection.createRange().text.length;

            Sel.moveStart('character', -el.value.length);

            pos = Sel.text.length - SelLength;

        }

        return pos;

    }

})(jQuery);

<textarea id="the_id_value">the text is an example</textarea>

                                                    

<a href="#"  $('#the_id_value').getCursorPosition() );

    return false;">点击我</a>