How to determine whether javascript contains a specified string

Judgment method: 1. Use the indexOf() method to obtain the first occurrence position of the specified string value. If the return value is "-1", it is not included; 2. Use the search() method to retrieve the specified string. If the return value is "-1", it is not included; 3. Use the match() method; 4. Use the test() method, etc.

The operating environment of this tutorial: windows7 system, javascript version 1.8.5, Dell G3 computer.

JavaScript determines whether the string contains the specified string

Method 1: indexOf() (recommended)

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

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

Method 2: search()

The search() method is used to retrieve the specified substring in the string, or to retrieve it with a regular expression Matching substring, if no matching substring is found, -1 is returned.

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

Method 3: match()

The match() method can retrieve a specified value within a string, or find one or more regular expressions formula matching.

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

Method 4: test()

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

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

Method 5: exec()

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.

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

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