How to add a custom text in popup

Hi,

I made popup window to appear when certain threshold is exceeded. But, I want in the window the value which is examining to be displayed, and I don't know how to insert that parameter inside the window. here is the code for the popup

 if(parseInt(mark[1].substring(0,2))>80)
                        {$("#dialog").dialog({
                                    buttons: {
                                        Close: function () {$(this).dialog('close');
                                        }
                                    }
                                });
                        }

I want mark[1] to appear in the window as text. I have this for the div

<div id="dialog" style="display: none">

Can anybody help me please how to insert the specific value (mark[1]) in the window?
Thanks