openlayers 2 - How to change the vertex style for editing?

When I use drag feature, then the circles on the polygon edge has the same style. For example, this OpenLayers site.

I need to change it, I mean they need to be a different color.

What is their (cycles) style attribute?

Answer

You should use vertexRenderIntent property of ModifyFeature control. For example:

var vertexStyle = {
    strokeColor: "#ff0000",
    fillColor: "#ff0000",
    strokeOpacity: 1,
    strokeWidth: 2,
    pointRadius: 3,
    graphicName: "cross"
}


var styleMap = new OpenLayers.StyleMap({
    "default": OpenLayers.Feature.Vector.style['default'],
    "vertex": vertexStyle
}, {extendDefault: false});

var layer = new OpenLayers.Layer.Vector('features', {styleMap: styleMap});
map.addControl(new OpenLayers.Control.ModifyFeature(layer, {vertexRenderIntent: "vertex"}));

At result we have the following style: