implement inheritance by object masquerading

<script language="javascript" type="text/javascript">
function clsA(){
    this.color="red";
    this.sayColor=function(){
        alert(this.color);
        }
    this.sayColorAgain=function(){
        alert(this.color);
    }
    
}
function clsB(){
    this.color="green";
    //this.prox=clsA;
    //this.prox();
    //delete this.prox;
    //clsA.call(this);
    clsA.apply(this);
}
var clsb=new clsB();
clsb.sayColor();
clsb.sayColorAgain();
</