blazor webassembly interop.someFunction not found

Question

I have this code in the index.html of my blazor webassembly project:

<div id="blazor-error-ui">
    An unhandled error has occurred.
    <a href="" class="reload">Reload</a>
    <a class="dismiss"></a>
</div>

<script src="_framework/blazor.webassembly.js"></script>
<script>navigator.serviceWorker.register('service-worker.js');</script>
<script src="_content/MudBlazor/MudBlazor.min.js"></script> 
<script src="js/jquery-3.4.1.min.js"></script>   
<script src="js/interop.js"></script>

and this is the interop.js file that is in the js folder of wwwroot. But I get error:

Unhandled exception rendering component: Could not find 'interop.disableDivInputs' ('disableDivInputs' was undefined)

I use this code:

await jsRuntime.InvokeVoidAsync("interop.disableDivInputs", "person");

and the interop.js is:

window.blazorCulture = {
    get: () => window.localStorage['BlazorCulture'],
    set: (value) => window.localStorage['BlazorCulture'] = value
};
window.interop = {
    setProperty: function (name, value) {
        localStorage.setItem(String(name).toLowerCase(), value);
        return value;
    },
    getProperty: function (name) {
        return (localStorage.getItem(String(name).toLowerCase()) || "");
    },
    setjson: function (key, value, location) {
        if (location === "LocalStorage") {
            localStorage.removeItem(String(key).toLowerCase());
            localStorage.setItem(String(key).toLowerCase(), value);
        }
        else {
            sessionStorage.removeItem(String(key).toLowerCase());
            sessionStorage.setItem(String(key).toLowerCase(), value);
        }
        return true;
    },
    getjson: function (key, location) {
        if (location === "LocalStorage") {
            return (localStorage.getItem(String(key).toLowerCase()) || "");
        }
        else {
            return (sessionStorage.getItem(String(key).toLowerCase()) || "");
        }
    },
    setObject: function (name, value) {
        try {
            localStorage.setItem(name, JSON.stringify(value));
            return true;
        }
        catch (e) {
            return false;
        }        
    },
    disableDivInputs: function (divId) {
        $(`#${divId} :input`).prop('readonly', true);
        $(`#${divId} :select`).prop('readonly', true);
    }
};

How to make this work?