While writing codes in javascript we have to declare variables but in the javascript we don't have the scope to declare multi data type variables .

Only var is available in the javascript that is treated as the common datatype but the var datatype provides many advantages to the programmers.

We can not only store single type value in it but it can also store the collection of items.

<script type="text/javascript">
    function initialize() {
        var markers = JSON.parse('<%=ConvertDataTabletoString() %>');
        var mapOptions = {
        center: new google.maps.LatLng(markers[0].lat, markers[0].lng),
zoom: 5,
mapTypeId: google.maps.MapTypeId.ROADMAP
//  marker:true
};
var infoWindow = new google.maps.InfoWindow();
var map = new google.maps.Map(document.getElementById("map_canvas"), mapOptions);
var image;
for (i = 0; i < markers.length; i++) {
var data = markers[i]
var myLatlng = new google.maps.LatLng(data.lat, data.lng);

var contentString = '<div id="content" style="margin-left:15px; margin-top:3px;overflow:hidden;">' +
'<div id="bodyContent">' + '<img src=' + data.image + ' style="width:172px;height:45px;"  alt="WebStreet.in"/>' + '<br><font style="color:darkblue;font:11px tahoma;margin-left:5px;">' + data.title + ' Your Trusted IT Solutions Provider</font>' +
'</div>' +
'</div>';


//var marker = new google.maps.Marker({

//position: myLatlng,
//map: map,
//title: data.title,
//});

var marker = new google.maps.Marker({
    map: map,
    // draggable:true,
    // animation: google.maps.Animation.DROP,
    position: myLatlng,
    title: data.title,
    icon: 'http://maps.google.com/mapfiles/kml/pal3/icon55.png' // null = default icon
});


    // Start of newly added code block

var infowindow = new google.maps.InfoWindow({
    content: contentString,
    width: 192,
    height: 100
});


(function (marker, data) {

    // Attaching a click event to the current marker
    google.maps.event.addListener(marker, "click", function (e) {
        infoWindow.setContent(data.description);
        infowindow.open(map, marker);
    });


    //google.maps.event.addListener(marker, "mouseover", function (e) {
    //    infoWindow.setContent(data.description);
    //    infowindow.open(map, marker);
    //});



})(marker, data);


}
    
     
        // End of newly added code block
    }



</script>

We don't have to do looping for inserting data into the var type variable it does it automatically.