How can I delete Red channel from image and use only Green merged to blue?

edit

I need to get an image and extract the color channels(RGB) and then merge Green and Blue ones, what am I doing wrong(Using OpenCV.js)

<button type="button" onclick="filter('Aneritra')">Aneritra</button>


<script>
    function filter(filter_name){
        if(filter_name == 'Aneritra'){
            let src = cv.imread('Selected_Image');
            let dst = new cv.Mat();
            let rgbaPlanes = new cv.MatVector();
            // Split the src
            cv.split(src, rgbaPlanes);
            // Get G channel
            let G = rgbaPlanes.get(1);
            // Get B channel
            let B = rgbaPlanes.get(2);
            // Merge G & B channels
            cv.merge((G,B), dst);
            cv.imshow('canvasOutput', dst);
            src.delete();
            dst.delete();
            rgbaPlanes.delete();
        }
    }
</script>