IndexOf method

 

* indexOf() method is used to identify a specific word is present in the String and it has 2 parameters. 

* Please note, the text given inside this method will do a Case-Sensitive comparison with the main String. 

* If there is no matching word then it will return "-1". If the given word is matching with the main String then it will return the starting index of the matching word.

For example:

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var mainString = 'Top Low'; mainString.indexOf('Low'); //output : 4 var mainString = 'Top Low'; mainString.indexOf('Low',3); //output : 4 var mainString = 'Top Low'; mainString.indexOf('L',3); //output : 4 var mainString = 'Top Low'; mainString.indexOf('L',5); //output : -1 , here we are giving instruction to start searching from Index 5.So there is no matching letter as a result it returned -1.

Application area:

To check for the occurrence of a search string inside a larger string, simply check

whether -1 was returned from .indexOf() method.

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function existsInString(stringValue, search) { return stringValue.indexOf(search) !== -1; }