JavaScript string indexOf Method

JavaScript String indexOf method search searchValue in string and return  index of first character of searchValue in string.

if searchValue not exist in string then string indexOf method return -1

Syntax

Example

<script>  var name = 'John the Don'  name.indexOf('Don'); // 9 </script>

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Parameter Details

Technical Details

Browser Support

Tips - When searchValue(substring) present more than one time in string then indexOf method return index of first searchValue

Example

<script> var name = 'John the Don is Don' name.indexOf('Don'); // 9 </script>

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fromIndex optional parameter

formIndex is optional parameter . it decide the index to start search in string and return index of searchValue if searchValue exist between startIndex and endIndex(last index of string)  otherwise return  -1

Example

<script> var name = 'John the Don is Don'  name.indexOf('Don',11); // 16 </script>

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indexOf() method  case-sensitive

indexOf()  method  search  searchValue(substring) as a case-sensitive

Example

<script>  var name = 'John the Don is Don'  name.indexOf('Don'); //9  name.indexOf('don'); //-1 </script>

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