Action Support With Repeater

<apex:repeat value="{!rowData}" var="var">   <td>

<apex:outputPanel >        
    <apex:outputText  value="{!var.RowValue}"/>           
    <apex:actionSupport event="onclick" action="{!myAction}" rerender="clickedCell">                     
      <apex:param name="ParamString" value="{!var.RowValue}"/>           
    </apex:actionSupport>     </apex:outputPanel>
   </td> 
</apex:repeat>

A parameter for the parent component. The < apex:param > component can only be a child of the following components:

< apex:actionFunction >
< apex:actionSupport >
< apex:commandButton >
< apex:commandLink >
< apex:outputLink >
< apex:outputText >
< flow:interview >

Note : The value ParamString will be binded with the var.RowValue what we are sending. And then get the ParmaString in your controller method and process the further.