Check if large size file exist quickly javascript

I have a web page which I need to check if files exist, they vary in files sizes and file type, I have the below code working but for larger files it can take a long time (one of them took 30 seconds) to return a result. What I want to know is there a better way, something that if it was a conversation would look like:

"Are you there file?"

"Yes. I am here and last Sunday I wa.. "

"ya, ya, ya your there shhh"

function fileExists(url) { 
    if(url){
        var req = new XMLHttpRequest()
        req.open('GET', url, false)
        req.send()
        return req.status==200
    } else {
        return false
    }
}

So anyone know of a better way which doesn't have to load as much of the file or can cancel the loading once it knows the file is there.