How to determine whether a string contains a certain string in javascript

Javascript method to determine whether a string contains a certain string: 1. Use the [indexOf()] method to return the position where a specified string value first appears in the string; 2. Use The [search()] method is used to retrieve a specified substring in a string.

The operating environment of this tutorial: Windows 7 system, JavaScript version 1.8.5, DELL G3 computer.

Javascript method to determine whether a string contains a certain string:

Method 1: indexOf()

var str = "123";
console.log(str.indexOf("3") != -1 );  // true

## The #indexOf() method returns the position of the first occurrence of a specified string value in a string. If the string value to be retrieved does not appear, the method returns -1.

Method 2: search()

var str = "123";
console.log(str.search("3") != -1 );  // true

The search() method is used to retrieve the substring specified in the string, or to retrieve the same Regular expression matching substring. If no matching substring is found, -1 is returned.

Method 3: match()

var str = "123";
var reg = RegExp(/3/);
if(str.match(reg)){
    // 包含        
}

The match() method can retrieve the specified value within the string, or find one or more A match of regular expressions.

Method 4: test()

var str = "123";
var reg = RegExp(/3/);
console.log(reg.test(str)); // true

The test() method is used to retrieve the value specified in the string. Returns true or false.

Method 5: exec()

var str = "123";
var reg = RegExp(/3/);
if(reg.exec(str)){
    // 包含        
}

The exec() method is used to retrieve matches of regular expressions in a string. Returns an array containing the matching results. If no match is found, the return value is null.

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