The only other way to open a new window is to use “target="_blank"” in your links or with your forms. But if you want control over the new windows then you have to use JavaScript.
To "slide in", you really need JavaScript. If it would be OK to just instantly appear, you could do that with CSS and a hover effect. In the future, when CSS3 has more support, CSS transitions will save us from having to use JavaScript from stuff like that.
Example :
http://www.dpopup.com/examples/scrolling1/dhtml-popup-scrolling1.html
But if you want control over the new windows then you have to use JavaScript.
can we show just instantly appear popup with only css automatically on page load like sample page