I changed it this way. But receive an error I can't fix<br><br>
<pre>kml_layer = new OpenLayers.Layer.Vector('KML', {
        projection: map.displayProjection,
        strategies: [
        new OpenLayers.Strategy.Fixed(),
        new OpenLayers.Strategy.CenteredCluster({
                zoomSettings: [
                        {zoomRange: [0, 2], settings: {distance: 100}},
                        {zoomRange: [3, 4], settings: {distance: 50}},
                        // 5 normal clusters
                        {zoomRange: [6, 7], settings: {threshold: 2}},
                        {zoomRange: [8, 99], settings: {enabled: false}}
                ]
        })
        ],
        styleMap: myClusterStyleMap, 
        protocol: new OpenLayers.Protocol.HTTP({
                url: filename,
                format: new OpenLayers.Format.KML({
                        extractStyles: true,
                        extractAttributes: true
                })
        })
});</pre><br><br>
My error message;<br><br>
<pre>TypeError: OpenLayers.Strategy.CenteredCluster is not a constructor  
{zoomRange: [8, 99], settings: {enabled: false}}</pre>

        
        
        
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