How to call function that inside JQuery Plugin From outside the plugin?

i am using textarea elastic plugin JQuery. this is the plugin

(function(jQuery){ 
jQuery.fn.extend({  
    elastic: function() {

        //  We will create a div clone of the textarea
        //  by copying these attributes from the textarea to the div.
        var mimics = [
            'paddingTop',
            'paddingRight',
            'paddingBottom',
            'paddingLeft',
            'fontSize',
            'lineHeight',
            'fontFamily',
            'width',
            'fontWeight'];

        return this.each( function() {

            // Elastic only works on textareas
            if ( this.type != 'textarea' ) {
                return false;
            }

            var $textarea   =   jQuery(this),
                $twin       =   jQuery('<div />').css({'position': 'absolute','display':'none','word-wrap':'break-word'}),
                lineHeight  =   parseInt($textarea.css('line-height'),10) || parseInt($textarea.css('font-size'),'10'),
                minheight   =   parseInt($textarea.css('height'),10) || lineHeight*3,
                maxheight   =   parseInt($textarea.css('max-height'),10) || Number.MAX_VALUE,
                goalheight  =   0,
                i           =   0;

            // Opera returns max-height of -1 if not set
            if (maxheight < 0) { maxheight = Number.MAX_VALUE; }

            // Append the twin to the DOM
            // We are going to meassure the height of this, not the textarea.
            $twin.appendTo($textarea.parent());

            // Copy the essential styles (mimics) from the textarea to the twin
            var i = mimics.length;
            while(i--){
                $twin.css(mimics[i].toString(),$textarea.css(mimics[i].toString()));
            }


            // Sets a given height and overflow state on the textarea
            function setHeightAndOverflow(height, overflow){
 开发者_如何转开发               curratedHeight = Math.floor(parseInt(height,10));
                if($textarea.height() != curratedHeight){
                    $textarea.css({'height': curratedHeight + 'px','overflow':overflow});

                }
            }


            // This function will update the height of the textarea if necessary 
            function update() {

                // Get curated content from the textarea.
                var textareaContent = $textarea.val().replace(/&/g,'&amp;').replace(/  /g, '&nbsp;').replace(/<|>/g, '&gt;').replace(/\n/g, '<br />');

                var twinContent = $twin.html();

                if(textareaContent+'&nbsp;' != twinContent){

                    // Add an extra white space so new rows are added when you are at the end of a row.
                    $twin.html(textareaContent+'&nbsp;');

                    // Change textarea height if twin plus the height of one line differs more than 3 pixel from textarea height
                    if(Math.abs($twin.height()+lineHeight/3 - $textarea.height()) > 3){

                        var goalheight = $twin.height()+lineHeight/3;
                        if(goalheight >= maxheight) {
                            setHeightAndOverflow(maxheight,'auto');
                        } else if(goalheight <= minheight) {
                            setHeightAndOverflow(minheight,'hidden');
                        } else {
                            setHeightAndOverflow(goalheight,'hidden');
                        }

                    }

                }

            }

            // Hide scrollbars
            $textarea.css({'overflow':'hidden'});

            // Update textarea size on keyup
            $textarea.keyup(function(){ update(); });
            $textarea.focus(function(){ update(); });

            // And this line is to catch the browser paste event
            $textarea.live('input paste',function(e){ setTimeout( update, 250); });             

            // Run update once when elastic is initialized
            update();

        });

    } 
}); 

})(jQuery);

How can i call from the outside of the plugin to the update function that is inside?

It you look at the bottom, it binds to the keyup and focus events here:

$textarea.keyup(function(){ update(); });
$textarea.focus(function(){ update(); });
//this should be just $textarea.keyup(update); but that's a another question :)

You can trigger the update() function by using .triggerHandler() for either of those event handlers, like this:

$('textarea').triggerHandler('keyup');