JS in blazor component

Question

I am trying create an alert message in within a Blazor component. I have no idea how to do this. I am running ASP.NET Core 3.1 Blazor server-side. Here's what I've tried

Component function:

private async Task ShowAlert()
    {
        await JSRuntime.InvokeAsync<object>("ShowMsg");
    }

Javascript Interop:

function ShowMsg() {
    success = "Success!";
    return success; 
}

File host.cshtml :

 <script src="~/BlazorInterop.js"></script>
    

Answer 1

@page "/"

<button @onclick="MessageBox">Show Message</button>

@code
{
    [Inject] IJSRuntime JSRuntime { get; set; }
    protected async Task MessageBox()
    {
       await JSRuntime.InvokeVoidAsync("exampleJsFunctions.ShowMsg", 
                                                    "Hello Blazor");
     }
}

Put the following script tag beneath <script src="_framework/blazor.server.js"></script> in the _Host.cshtml file, like this:

<script src="_framework/blazor.server.js"></script>
<script>
    window.exampleJsFunctions =
    {
        ShowMsg: function (message) {
            window.alert(message);
        }
    };
</script>