Check if Div with specific Class exists in the page

[Nakatsura]

I'm trying to modify an existing webpage by inserting my own Javascript file in it. I'm setting a background Image for this webpage by inserting a new Div through my Javascript and setting background of that div to image url. For centering this image on background and to make it occupy the whole webpage, I'm using \[code\]'background-size': 'cover'\[/code\]property. This of course doesn't work in older IE versions.I want to fix it, I'm thinking of zooming in the image by specific ratio calculated using page height/width and image height/width.So I want to detect if browser is IE. I checked the webpage and it has this code that detects browser and add's a div with class IE. \[code\]<!--[if lte IE 5]> <div class="ie"><![endif]--><!--[if IE 6]> <div class="ie ie6"><![endif]--><!--[if IE 7]> <div class="ie ie7"><![endif]-->\[/code\]My questions is how do I detect if this page has a div with class ie. Also, I would really appreciate if someone could suggest an alternative way of setting a background image on the webpage page that occupies it fully irrespective of dimensions of image/page and image center is focused.