Place cursor at the end of an iframe content

I have an iframe in which I want to add images dynamically with php. Each image should be followed by a line break and so that the next image added to be added in the following row. The line break is added but the focus stays a开发者_开发知识库lways at the beginning of the iframe content (when it should have been at the end of the newly added <br> tag). Is there a way to move the cursor to the end of the content of the iframe with Javascript which works with all browsers?

What about setting scrollTop or calling scrollTo?