Using Floating technique

we can use floating and it does not need position defined for the main content see the following example. Also it is most popular way in positioning:

#mainContent{

Padding:15px;

Margin: 15px auto;

Width:720px;

Border 1px Solid black;

Background-Color:#eef;

}

#first{

Float:left;

Padding:15px;

Width:330px;

}

#second{

Float:left

Padding:15px;

Width:330px;

}

after applying floating the main content like background color might not continue for that usually you use an empty P tag with the following class:

.clear {

    clear: both;

    height: 0;

    margin: 0;

    padding: 0;

}