<script type="text/javascript" language="javascript">
function CloseW(dateR){
window.returnValue=dateR
alert(window.returnValue)
window.close()
}
</script> 

<script language="javascript"type="text/javascript" >
 function OpenD(tb_object_name){
  var r=window.showModalDialog("Calendar.aspx",null,
	"dialogWidth:100px;menubar:0;dialogHeight:250px");
  if (r!=null && r!=""){
     // document.all(tb_object_name).disabled=false;
      document.all(tb_object_name).value=r; 
      }
}
</script>

<input id="tb_date_start" runat="server" type="text"  />
                   
                    <img alt="Календарь" src="images/Calendar.png" runat="server" onclick="OpenD('tb_date_start')" id="IMG1"/>
                  

var ref=window.open("calendar.html", "Calendar","modal=yes");

   <script language="javascript"type="text/javascript" >
 function OpenD(tb_object_name){
    var appOptions=new Array( 2 );
    appOptions[ 0 ]=window.self;   
    appOptions[ 1 ]=tb_object_name;
    alert("appOptions[0]="+appOptions[ 0 ]+"appOptions[1]="+appOptions[ 1 ]);
    
  var r=window.showModalDialog("Calendar.aspx",appOptions,
	"dialogWidth:250px;menubar:0;status:0;dialogHeight:250px");
	
  if (r!=null && r!=""){
  alert(r);
    
     document.all(tb_object_name).value=r; 
      }
}
</script>

 <script type="text/javascript" language="javascript">
function CloseW(dateR){

var appOptions=new Array( 2 );
appOptions=window.dialogArguments;

alert("window.opener="+window.opener+"appOptions[0]="+appOptions[ 0 ]);
//window.opener.document.all[appOptions[ 1 ]].value=dateR;
appOptions[ 0 ].document.all[appOptions[ 1 ]].value=dateR;
window.close();
}
</script>