What is the use of UriHelper in Blazor?

The IUriHelper services are used for navigation and routing in Blazor. But IUriHelper service in Blazor has been replaced by NavigationManager from .NET Core 3.0 Preview 9. For more details refer to this link.

Does Blazor support lower versions of IE11?

No, Blazor WebAssembly (client-side Blazor) does not support any version of Internet Explorer due to the lack of WebAssembly support in IE. However, server-side Blazor can be made compatible with IE 11 by using additional polyfills to bridge the gaps in browser support.

How do I serialize and deserialize JSON in a Blazor application?

JSON (JavaScript Object Notation) is a lightweight data-interchange format and a text format that is language independent. In Blazor, the JsonSerializer class, found in the System.Text.Json namespace, assists with serializing and deserializing JSON data. [index.razor] In the provided sample, JsonSerialize.Serialize(object) is used to serialize the user object of the User class into a string. Then, JsonSerialize.Deserialize<ClassName>(JsonObject) is used to deserialize the serializedString string into a new instance of the User class named userCopy. 

Is Blazor supported by IE?

Only server-side Blazor is supported by Microsoft’s Internet Explorer IE 11 when additional polyfills are used. Client-side Blazor is not supported by Internet Explorer due to incompatibility of WebAssembly. You need to add the following polyfills in the _Host.cshtml/_Layout.cshtml page to support Internet Explorer. [_Host.cshtml/_Layout.cshtml]

How to call JavaScript methods from the Blazor (.razor) pages?

You can call JavaScript methods from the Blazor pages with the help of JavaScript Interop by injecting the dependency IJSRuntime into the razor page. Then refer the script in the HTML page of the blazor application. Check this link for more information.