There are three pages displayed at the same time, lesson2, lesson3, and this explanation. we simply split the screen into three parts and placed a different page in each part.Lets look at the source code first before we start explainig what it means:
FRAMESET starts any frame page. It alerts the browser that FRAMES are going to be present. COLS is a way of defining how we want the frame to look like. It stands for columns. we can also use raws (raw). The percentages above, demonstrates how much space of the screen each frame will use. Notice that we used 99%, the browser will distribute the remaining 1% by itself. FRAME SRC denotes the source of the frame. Frames read like us, left to right. The first source offered will be hard left an the remainig will come to the right. /FRAMESET will end the the whole thing.