问Youtube UploadWidget上的onUploadStart？

EN

var stack = [];

function onStateChange(event) {
    var state = event.data.state;
    switch (state) {
        case YT.UploadWidgetState.RECORDING:
            break;
        case YT.UploadWidgetState.PENDING:
            break;
        case YT.UploadWidgetState.STOPPED:
            if(stack.pop() == "US")
            {
              //video is uploaded and processing has been started, I show loader here
                stack.push("US");
            }
            stack.push("S");
            break;
    }
}

function onUploadSuccess(event) {
    stack.push("US");
}

function onProcessingComplete(event) {
    if(stack.pop() == "S" && stack.pop() == "US")
    {
        stack = [];
    }
//disable spinner
}