var TextareaHelper = {
    resize:function(element){
        if(!element.attr('orign_rows')){
            element.attr('orign_rows',element.attr('rows'));
        }
        var num_min_rows = parseInt(element.attr('orign_rows'));
        var rows = parseInt(element.attr('rows'));
        var cols = parseInt(element.attr('cols'));
        var str_text = element.attr('value');
        var num_rows = 1;
        if(str_text){
            var arr_rows = str_text.split("\n");
            num_rows = arr_rows.length;
            var i = 0;
            for(i=0;i<num_rows;i++){
                if(arr_rows[i]){
                    var text_row = arr_rows[i];
                    if(text_row.length >0 && text_row.length>cols){
                        num_rows += Math.floor(text_row.length/cols);
                    }
                }
            }
        }
        var num_rows_optimal = num_rows+2;
        if(num_rows_optimal<num_min_rows){
            num_rows_optimal = num_min_rows;
        }
        if(num_rows_optimal!=rows){
            element.attr('rows',num_rows_optimal);
        }
    }
};
$(document).ready(function() {
    $('textarea').keyup(function () {
        TextareaHelper.resize($(this));
    });
    $('textarea').each(function () {
        TextareaHelper.resize($(this));
    });
});