Function setCapture

systemvm/agent/noVNC/core/util/events.js:63–108

(target)

const _captureObserver = new MutationObserver(_capturedElemChanged);

export function setCapture(target) {
    if (target.setCapture) {

        target.setCapture();
        document.captureElement = target;
    } else {
        // Release any existing capture in case this method is
        // called multiple times without coordination
        releaseCapture();

        let proxyElem = document.getElementById("noVNC_mouse_capture_elem");

        if (proxyElem === null) {
            proxyElem = document.createElement("div");
            proxyElem.id = "noVNC_mouse_capture_elem";
            proxyElem.style.position = "fixed";
            proxyElem.style.top = "0px";
            proxyElem.style.left = "0px";
            proxyElem.style.width = "100%";
            proxyElem.style.height = "100%";
            proxyElem.style.zIndex = 10000;
            proxyElem.style.display = "none";
            document.body.appendChild(proxyElem);

            // This is to make sure callers don't get confused by having
            // our blocking element as the target
            proxyElem.addEventListener('contextmenu', _captureProxy);

            proxyElem.addEventListener('mousemove', _captureProxy);
            proxyElem.addEventListener('mouseup', _captureProxy);
        }

        document.captureElement = target;

        // Track cursor and get initial cursor
        _captureObserver.observe(target, {attributes: true});
        _capturedElemChanged();

        proxyElem.style.display = "";

        // We listen to events on window in order to keep tracking if it
        // happens to leave the viewport
        window.addEventListener('mousemove', _captureProxy);
        window.addEventListener('mouseup', _captureProxy);
    }
}

export function releaseCapture() {
    if (document.releaseCapture) {