Divide webpage coloumns into the divisions

header, left content, right content.and set from the css file. my problem is that once i click on the left content's link button so page redirected but i want once i click on any link buttons which is on the left container so page should be open into the right container.

<form id="form1" runat="server">
    <div id="maincontainer">
    <div id="header">

        <div id="logo">
            <img src="images (3).jpg" alt="DSIIDC" />
       </div>

         <div id="container">


            <div id="leftContainer">
                <a href="#"></a><br />
                <a href="WebForm1.aspx">Receive</a><br /><br />
                   <a href="#">Receive</a>
             </div>
            <div id="RightContainer"></div>
        </div>
    </form>

my css file is blow

body {
      font-family:'Times New Roman'; font-style:normal;
}
html {
    font-family:'Times New Roman';  font-size:14pt;
}
#maincontainer {
    border:1px solid; width:1000px; height:700px;  margin:0 auto;  padding:13px; background-color:#E3B58A;
}

#header {

    border:1px solid;  height:100px;
}

#logo {
    padding:0px; margin:5px 3px;

}

#container {
    width:997px; height:420px;   border:1px solid; margin:10px 0 0 0;
}
#leftContainer {
    width:20%; height:420px;  float:left; background-color:red;

}

#RightContainer {
    width:80%; height:420px; float:right; background-color:gray;

}

ul {
    list-style:none;
}