It may have been used at one point, perhaps by older versions of IE, but it looks like it's time to not allow that anymore so I've removed support for this going forward.
The correct attribute to use is "frameborder" (but see below).
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As we found out before, the code some larger companies provide, don't always provide a code that is html/xhtml valid. found out that the code problem gave, was basically just that all "&" in the code had to be changed to the correct "&".
This time it's who provide a code that's not html/xhtml valid.
It looks like that is what was given to you but it changed to "border" somehow.
Another issue: "frameborder" is not allowed in HTML5.