<apex:column >
   <apex:commandLink value="Click" action="{!meth1}" target="_blank" onclick="methodInJavascript();">
        <apex:param value="{!ll.Mobile__c}" assignTo="{!toMObile}" name="assignvalue" />
   </apex:commandlink>
</apex:column>


 <apex:actionFunction action="{!meth2}" name="methodInJavascript" />

public PageReference meth2() {
    Pagereference p2 = new  Pagereference('https://ap2.salesforce.com/a0A28000000okkjEAA/e');
p2.setredirect(true);

return p2;
    }


    public PageReference meth1() {
    Pagereference p1 = new Pagereference('https://www.google.com');
p1.setredirect(true);

return p1;
    }

<apex:column >
   <apex:commandLink value="Click" action="{!meth1}" target="_blank" onclick="window.open('https://ap2.salesforce.com/a0A28000000okkjEAA/e')">
        <apex:param value="{!ll.Mobile__c}" assignTo="{!toMObile}" name="assignvalue" />
   </apex:commandlink>
</apex:column>

<apex:page controller="testController">
    <p onclick="openTwoWindows()">Click</p>
    <script type="text/javascript">
    function openTwoWindows()
    {
    window.open("http://www.google.com");
    window.open("http://www.google.com");
    }
    </script>
</apex:page>