Cara menggunakan execution context in javascript
Summary: in this tutorial, you will learn about the JavaScript execution context to deeply understand how JavaScript code gets executed. Introduction to the JavaScript execution contextLet’s start with the following example:
In this example:
Behind the scene, JavaScript does many things. in this tutorial, you will focus on execution contexts. When the JavaScript engine executes the JavaScript code, it creates execution contexts. Each execution context has two phases: the creation phase and the execution phase. The creation phaseWhen the JavaScript engine executes a script for the first time, it creates the global execution context. During this phase, the JavaScript engine performs the following tasks:
When the JavaScript engine executes the code example above, it does the following in the creation phase:
After the creation phase, the global execution context moves to the execution phase. The execution phaseDuring the execution phase, the JavaScript engine executes the code line by line, assigns the values to variables, and executes the function calls. For each function call, the JavaScript engine creates a new function execution context. The function execution context is similar to the global execution context. But instead of creating the global object, the JavaScript engine creates the In our example, the function execution context creates the During the execution phase of the function execution context, the JavaScript engine assigns To keep track of all the execution contexts, including the global execution context and function execution contexts, the JavaScript engine uses the call stack, which you will learn in the next tutorial. In this tutorial, you have learned about the JavaScript execution contexts, including the global execution context and function execution contexts. |