you could use this:

var myStyle= {fillColor: "#ff0000"};
            
             var BounderyshpLayer = new OpenLayers.Layer.Vector({
             projection: new OpenLayers.Projection('EPSG:3826'),
             style: myStyle
             });

see: http://jsfiddle.net/expedio/2xvfbtdw/

or even use a stylemap with different style for default and select:

var defStyle = {fillColor: "#ff0000",strokeColor: "green", strokeOpacity: "0.7", strokeWidth: 3, cursor: "pointer"};
        var sty = OpenLayers.Util.applyDefaults(defStyle, OpenLayers.Feature.Vector.style["default"]);
        
        var sm = new OpenLayers.StyleMap({
            'default': sty,
            'select': {strokeColor: "red", fillColor: "green"}
        });
        
        var BounderyshpLayer = new OpenLayers.Layer.Vector({
             projection: new OpenLayers.Projection('EPSG:3826'),
             styleMap: sm,
             });

see: http://jsfiddle.net/expedio/yxr5wdjo/

nice website with Information about the Feature-Style and Stylemap: http://www.peterrobins.co.uk/it/olstyle.html

you could use this:

var myStyle= {fillColor: "#ff0000"};
            
             var BounderyshpLayer = new OpenLayers.Layer.Vector({
             projection: new OpenLayers.Projection('EPSG:3826'),
             style: myStyle
             });

see: http://jsfiddle.net/expedio/2xvfbtdw/

or even use a stylemap with different style for default and select:

var defStyle = {fillColor: "#ff0000",strokeColor: "green", strokeOpacity: "0.7", strokeWidth: 3, cursor: "pointer"};
        var sty = OpenLayers.Util.applyDefaults(defStyle, OpenLayers.Feature.Vector.style["default"]);
        
        var sm = new OpenLayers.StyleMap({
            'default': sty,
            'select': {strokeColor: "red", fillColor: "green"}
        });
        
        var BounderyshpLayer = new OpenLayers.Layer.Vector({
             projection: new OpenLayers.Projection('EPSG:3826'),
             styleMap: sm,
             });

see: http://jsfiddle.net/expedio/yxr5wdjo/

nice website with Information about the Feature-Style and Stylemap: http://www.peterrobins.co.uk/it/olstyle.html

PS: Just for demonstration purposes: If you open your website and use the console of your debug-tool (firebug for example) you run this code in your developer tools (non permanent change of course):

map.layers[2].style={fillColor: "#ff0000",fillOpacity:"0.5"};map.layers[2].redraw();

have a look at the screenshot:

you could use this:

var myStyle= {fillColor: "#ff0000"};
            
             var BounderyshpLayer = new OpenLayers.Layer.Vector({
             projection: new OpenLayers.Projection('EPSG:3826'),
             style: myStyle
             });

see: http://jsfiddle.net/expedio/2xvfbtdw/

you could use this:

var myStyle= {fillColor: "#ff0000"};
            
             var BounderyshpLayer = new OpenLayers.Layer.Vector({
             projection: new OpenLayers.Projection('EPSG:3826'),
             style: myStyle
             });

see: http://jsfiddle.net/expedio/2xvfbtdw/

or even use a stylemap with different style for default and select:

var defStyle = {fillColor: "#ff0000",strokeColor: "green", strokeOpacity: "0.7", strokeWidth: 3, cursor: "pointer"};
        var sty = OpenLayers.Util.applyDefaults(defStyle, OpenLayers.Feature.Vector.style["default"]);
        
        var sm = new OpenLayers.StyleMap({
            'default': sty,
            'select': {strokeColor: "red", fillColor: "green"}
        });
        
        var BounderyshpLayer = new OpenLayers.Layer.Vector({
             projection: new OpenLayers.Projection('EPSG:3826'),
             styleMap: sm,
             });

see: http://jsfiddle.net/expedio/yxr5wdjo/

nice website with Information about the Feature-Style and Stylemap: http://www.peterrobins.co.uk/it/olstyle.html