JavaScript not equals symbol

JavaScript is a widely used scripting language that is often used in web development. In JavaScript, the not equals symbol is a common keyword in development. In this article, we will discuss JavaScript’s inequality symbol from the following aspects.

1. JavaScript’s inequality symbol (!=)

The inequality symbol (!=) in JavaScript is a comparison operator, which is used to determine whether two values ​​are not equal. This operator returns true when the two values ​​are not equal and false when the two values ​​are equal. The following is a simple example:

var x = 10;
var y = 5;
if (x != y) {
console.log("x and y are not equal ");
}

In the above code, when x is not equal to y, JavaScript will execute the code block in the if statement and output the result "x and y are not equal". On the other hand, if they are both equal, they will not be executed.

2. JavaScript’s strict inequality symbol (!==)

In addition to the inequality symbol (!=), JavaScript also provides a strict inequality symbol (!==). It differs from the inequality symbol in that it not only compares whether two values ​​are equal, but also compares the data types of the two values. The strict inequality symbol returns true when the two values ​​are neither equal nor of different data types. The following is an example:

var x = 10;
var y = "10";
if (x !== y) {
console.log("x and y are not the same are equal, and their data types are different");
}

In the above example, although the values ​​​​of x and y are equal, their data types are different (one is a numeric type, and the other is a character String type), therefore, JavaScript will execute the code block in the if statement and output the result "x and y are not equal, and their data types are different."

3. The operation of JavaScript's inequality symbol when comparing objects

When JavaScript uses the inequality symbol (!=) to compare two objects, it will compare whether they refer to the same Object. If the same object is referenced, the comparison is false; otherwise, the comparison is true.

The following is an example:

var person1 = { name: "John" };
var person2 = { name: "John" };
if (person1 != person2) {
console.log("person1 and person2 do not reference the same object");
}

In the above code, although the attribute values ​​​​of person1 and person2 are the same, they refer to The objects are different, so JavaScript will execute the code block in the if statement and output the result "person1 and person2 do not reference the same object".

4. It is recommended to use the strict inequality symbol

Although the inequality symbol (!=) and the strict inequality symbol (!==) in JavaScript can be used to compare values ​​of different types , but in actual development, it is recommended to use strict inequality symbols for comparison. This is because using the strict inequality symbol can avoid implicit type conversion problems during comparison, making it safer and more reliable.

5. Summary

JavaScript’s inequality symbol is one of the comparison operators commonly used in development. When using the inequality notation, it compares whether the two values ​​are unequal; when using the strict inequality notation, it compares the data types of the two values. Additionally, when comparing objects, JavaScript compares whether they refer to the same object. It is recommended to use strict inequality notation in development to improve code readability and robustness.

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