How to change background colour of a selected row of a page block table?

<apex:page standardController="Account" recordSetVar="accounts" sidebar="false">
    <style>
    .rowColor {
            background-color:orange;
            }
    </style>
    <script>
        var pRow='';
        function highlightElem(a) {             
            var c=a.className;
          //  alert(c);
            a.className="rowColor";
            if(pRow==''){
                pRow=a;
            }
            else {
                if(pRow.innerHTML!=a.innerHTML) {
                    pRow.className=c;
                    pRow=a;
                }
            }
        }
    </script>
        <apex:form >
        <apex:pageBlock >
            <apex:PageBlockTable value="{!accounts}" var="r" onRowClick="highlightElem(this)" >
                <apex:column value="{!r.Name}" />
                <apex:column value="{!r.Phone}" />
                <apex:column value="{!r.Type}" />
            </apex:PageBlockTable>
        </apex:pageBlock>
    </apex:form>
</apex:page>