Null on this line:

 console.log("Using libheif", libheif.heif_get_version());
 
> Uncaught TypeError: libheif.heif_get_version is not a function   at window.onload (libheif/:314:46)

But it works fine if I reload.  execution order maybe?
 
```

    window.onload = function() {
        hide("loading");
        if (typeof libheif === "undefined") {
            alert("libheif could not be loaded, please check your browser console for details.");
            return;
        }

        console.log("Using libheif", libheif.heif_get_version());
        var demo = new HeifDemo(libheif);

        show("form");
```
null in js demo https://strukturag.github.io/libheif/
This is a GitHub Issue
repo:libheif
owner:strukturag
Title : null in js demo https://strukturag.github.io/libheif/
Issue date:

--- start body ---
Null on this line:

 console.log("Using libheif", libheif.heif_get_version());
 
> Uncaught TypeError: libheif.heif_get_version is not a function   at window.onload (libheif/:314:46)

But it works fine if I reload.  execution order maybe?
 
```

    window.onload = function() {
        hide("loading");
        if (typeof libheif === "undefined") {
            alert("libheif could not be loaded, please check your browser console for details.");
            return;
        }

        console.log("Using libheif", libheif.heif_get_version());
        var demo = new HeifDemo(libheif);

        show("form");
```
--- end body ---
