How to apply CSS effect in “old” browsers

Rather a bookmark to myself, I found this useful link dated back in 2009 but still in use, I wanted to show some opacity filter (RGBa) on a DIV Background but my client had mainly IE7 browsers.
This tool will convert RGBA or HSLA into –ms–filter (for IE8) and –filter (IE6 & 7)
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Click the image to open the RGBa & HSLa CSS Generator for Internet Explorer on KIMILI.COM