I had to look this up because I don't believe iframe has a border attribute or ever had. Well it did, but it was called frameborder and is now obsolete use CSS instead.
Found it here http://dev.w3.org/html5/markup/iframe.html
Maybe the best explanation comes from Mozilla Developer Network here https://developer.mozilla.org/en-US/...Element/iframe
which gives us this:
Indicates the height of the frame HTML5 in CSS pixels, or HTML 4.01 in pixels or as a percentage.
Indicates the width of the frame HTML5 in CSS pixels, or HTML 4.01 in pixels or as a percentage.
frameborder HTML 4 only
The value 1 (the default) tells the browser to draw a border between this frame and every other frame. The value 0 tells the browser not to draw a border between this frame and other frames.
If your still having problems please post the iframe tag with attributes and/or the CSS you are using.