JavaScript String Functions Demonstration

(1) var str="New Hampshire Dept. of Corrections Special School District" ;

Original string: 

(2) var length1 = str.length ;

The original string contains characters.

Note that the string length (character count) includes spaces.  Also note that length is a property, not a function.  This is why length is not followed by parentheses.

(3) var space1 = str.indexOf( " " ) ;

The first space is at character position: 

Note that the character position is 0-based!

(4) var word1 = str.substr( 0, space1 ) ;

The first word is: 

The substr parameters are the starting position and the number of characters.

(5) var space2 = str.indexOf( " ", space1+1 ) ;

The second space is at character position: 

The second parameter tells JavaScript where to start the character search.

(6) var word2 = str.substr( space1+1, space2-space1 ) ;

The second word — extracted using the substr function — is: 

Remember that the second parameter to the substr function is the number of characters, not the ending space.  This is why we have to subtract space1 from space2.

(7) var word2b = str.substring( space1+1, space2 ) ;

The second word — extracted using the substring function — is: 

The second parameter to the substring function is indeed the ending space.  This is why we do not subtract space1 from space2.

(8) var phrase1 = word2 + " " + word1 ;

Concatenating word1 onto word2 yields: 

Remember that the second parameter is the number of characters, not the ending space.  This is why we have to subtract space1 from space2.

(9) var arrWords = str.split( " " ) ;

We can get all the words at once using the split function:

Note that array indexes are 0-based!

(10) document.writeln( arrWords[5] + " " + arrWords[7] + " " + arrWords[3] + " " +
    arrWords[1] + " " + arrWords[0] + " " + arrWords[6] + " " + arrWords[4] ) ;

We can then print them any way we want! 

(11) var phrase2 = str.replaceAll( " ", "|" ) ;

Replacing all spaces with vertical bars yields: 

The first parameter is the search string and the second is the replacement string.

(12) var bStartsWithNew = str.startsWith( "New" ) ;

Testing whether the string starts with New yields: 

(13) var bEndsWithNew = str.startsWith( "Hampshire" ) ;

Testing whether the string ends with Hampshire yields: 

(14) var strUpper = str.toUpperCase() ;

Converting the string to all uppercase yields: 

(15) var strLower = str.toLowerCase() ;

Converting the string to all lowercase yields: 

(16) var bIncludesSchool1 = str.includes( "School" ) ;

Testing whether the string includes (contains) School yields: 

Note that the includes function is case-sensitive.  This is verified by the next example.

(17) var bIncludesSchool2 = str.includes( "school" ) ;

Testing whether the string includes school yields: