Settings{
    left: 100, // left position of dialog box''
    top: 100, // top position of dialog box 
    hideinterval: 0, // can provide auto hide interval
    hideOnClick: false, // set true to hide popup on click
    draggable: true, // set this flag true to make dialog draggable
    draggableContainer: "document", // set dialog draggable boundaries , default is document, you can pass $("#divid")
    enableclose:true, // set true to show close link
    closeIcon:"close_icon.jpg", // set close icon
    ismodal: true, // create model dialog 
    overlayStyle:{
        opacity: 0.1, // set opacity for overlay
        background:'black', // set overlay div color
        extraCSS:'' // set css properites to customize overlay css 
    },
    popupStyle:{
        border: 3, // border width of dialog box
        bordercolor: '#000', // border color of dialog box
        borderradius: 10, // border radius of dialog // do not work in IE
        background:'#dddddd', // dialogbox background color.
         extraCSS:'' // you can provide extra css properties to customize popup window
    }
}

 <script type="text/javascript" src="https://ajax.googleapis.com/ajax/libs/jquery/1.7.1/jquery.min.js"></script>
 <script type="text/javascript" src="https://ajax.googleapis.com/ajax/libs/jqueryui/1.8.16/jquery-ui.js"></script>
 <script type="text/javascript" src="https://github.com/downloads/ajayhada/SimpleDialog/SimpleDialog-2.0.js"></script>

<div class="Hello" style="display:none;">
    <h1>Hello guys</h1>
    <b>Hello guys</b>
    <b>Hello guys</b>
</div>

function closePopup(){
    $('.Hello').closeAllpopup();   
}

function show(){
    $('.Hello').showpopup({enableclose:true,closeIcon:"close_icon.gif",ismodal:true,overlayStyle:{background:"RED"}});
}

<button onclick="show();">Click to open popup box</button>