js intercepts strings to record small searches in daily development

In JavaScript, you can use substring()the and substr()methods to intercept a string.

substring(startIndex [, endIndex])method is used to extract a substring from a string.

• startIndexThe parameter is required, indicating the starting position of the substring to be intercepted.
• endIndexThe parameter is optional, indicating the end position of the substring to be intercepted. If omitted, it will be truncated to the end of the string.

substring()method returns a new string and does not modify the original string.

For example, assuming there is a string "Hello, world!", to intercept from the 7th character, you can use the following code:

const str = "Hello, world!";
    const subStr = str.substring(7);
    console.log(subStr); // 输出 "world!"

If you want to intercept from the first character to the fifth character, you can use the following code:

const str = "Hello, world!";
    const subStr = str.substring(0, 5);
    console.log(subStr); // 输出 "Hello"

substr(startIndex [, length])method is used to extract a substring from a string.

• startIndexThe parameter is required, indicating the starting position of the substring to be intercepted.
• lengthThe parameter is optional and indicates the length of the substring to be truncated. If omitted, it will be truncated to the end of the string.

substr()method returns a new string and does not modify the original string.

• For example, assuming there is a string "Hello, world!", to intercept from the 7th character, you can use the following code:

const str = "Hello, world!";
    const subStr = str.substr(7);
    console.log(subStr); // 输出 "world!"

If you want to intercept 5 characters starting from the first character, you can use the following code:

const str = "Hello, world!";
    const subStr = str.substr(0, 5);
    console.log(subStr); // 输出 "Hello"