I am interested in algorithms and data structures, I care about code quality to reduce the maintenance costs and to make the code more debug-able and bug free. also, I care about performance and to use the right algorithm in the right place.
I've two years of experience as Java software developer at a well known companies, I worked on projects for banking systems and search engines in which not only correctness but also performance, code readability and maintainability are important.
As an answer to your question, yes you can remove the header and the footer from the website in the iframe using javascript which run after iframe loading, but it will not work if the user disabled JavaScript on his browser, also problems may occur if the website changes something on the DOM elements which you select and remove with JavaScript, so you must be careful and expect all the scenarios and acceptable alternative solutions in all of them.