JavaScript: Count number of words in string

Last update on March 06 2025 10:56:49 (UTC/GMT +8 hours)

JavaScript validation with regular expression: Exercise-6 with Solution

Count Words in String

Write a JavaScript program to count number of words in string.

The script will be used to:

- Remove white-space from start and end position.
- Convert 2 or more spaces to 1.
- Exclude newline with a start spacing.

Visual Presentation:

JavaScript: Count number of words in string

Sample Solution:

HTML Code:

<!DOCTYPE html>
  <html>
  <head>
  <meta charset=utf-8 />
  <title>Count number of words in a string</title>
  <style type="text/css">
  body {margin-top: 40px;}
  </style> 
</head>
  <body>
  <textarea id="InputText" cols="30" rows="4">The quick brown fox jumps over the lazy dog.</textarea>
  <br>
  <input type="button" name="Convert" value="No. of Words" onClick="count_words();">
  <input id = "noofwords" type="text" value="" size="6"> 
  </body>
  </html>

JavaScript Code:

function count_words()
{
str1= document.getElementById("InputText").value;
//exclude  start and end white-space
str1 = str1.replace(/(^\s*)|(\s*$)/gi,"");
//convert 2 or more spaces to 1  
str1 = str1.replace(/[ ]{2,}/gi," ");
// exclude newline with a start spacing  
str1 = str1.replace(/\n /,"\n");
document.getElementById("noofwords").value = str1.split(' ').length;
}

Output:

The quick brown fox jumps over the lazy dog.
  
9

Live Demo:

For more Practice: Solve these Related Problems:

Write a JavaScript function that counts the number of words in a string by first trimming and then splitting by whitespace.
Write a JavaScript function that collapses multiple spaces into one and returns the accurate word count.
Write a JavaScript function that excludes punctuation from words before counting the total number.
Write a JavaScript function that accepts a string with newline characters and counts words correctly across lines.

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