Combined Bank (HBFC and BKB) Assistant Programmer Written Test: 2018প্রশ্ন ও সমাধান

The .NET Framework is Microsoft's software development platform for building and running Windows applications and web services.

Component	Role
CLR (Common Language Runtime)	The execution engine — manages memory (garbage collection), JIT-compiles IL to native code, enforces type safety and security
CTS (Common Type System)	Defines how types are declared, used, and managed, enabling cross-language interoperability
CLS (Common Language Specification)	A set of rules every .NET language must follow so components written in different languages can interoperate
BCL / FCL (Base/Framework Class Library)	A huge library of reusable classes for I/O, collections, networking, etc.
ADO.NET	Data access technology for connecting to and manipulating databases
ASP.NET	Framework for building web applications and web services
Windows Forms / WPF	Frameworks for building desktop GUI applications
CIL/MSIL (Common Intermediate Language)	The intermediate, platform-neutral code produced by .NET compilers before JIT compilation

graph TD
  Src["Source Code (C#, VB.NET, F#)"] --> Comp[Language Compiler]
  Comp --> IL["CIL / MSIL + Metadata"]
  IL --> CLR["CLR: JIT Compiler, GC, Security"]
  CLR --> Native[Native Machine Code Execution]

Exam takeaway: the CLR is the runtime heart of .NET (memory management + JIT), the CTS/CLS enable language interoperability, and the BCL/ASP.NET/ADO.NET provide the actual application-building libraries.

The HTML DOM (Document Object Model) represents an HTML page as a tree of objects; JavaScript can use DOM methods to read or change any element's attributes at runtime.

Method: element.setAttribute(name, value) sets (or updates) an attribute; element.getAttribute(name) reads it; element.removeAttribute(name) deletes it.

<!DOCTYPE html>
<html>
<head>
<style>
  .highlight { color: red; font-weight: bold; }
</style>
</head>
<body>
  <h1 id="title">Hello World</h1>
  <button onclick="myFunction()">Try it</button>

  <script>
    function myFunction() {
      const heading = document.getElementById("title");
      heading.setAttribute("class", "highlight");   // change the class attribute
    }
  </script>
</body>
</html>

How it works: document.getElementById("title") locates the DOM node; .setAttribute("class", "highlight") then changes its class attribute at runtime, which immediately applies the CSS rule bound to .highlight — the page updates without a reload.

Other common attribute changes: img.setAttribute("src", "new.jpg"), link.setAttribute("href", "page2.html"), or directly via the property shortcut element.className = "highlight".

Exam takeaway: setAttribute()/getAttribute() are the general DOM API for any attribute; many common attributes (class, id, value, src) also have direct JavaScript property shortcuts.