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JavaScript: Check whether a string starts with 'Java' and false otherwise

JavaScript Basic: Exercise-27 with Solution

Write a JavaScript program to check whether a string starts with 'Java' and false otherwise.

Pictorial Presentation:

JavaScript: Check whether a string starts with 'Java' and false otherwise

Sample Solution:

HTML Code:

<!DOCTYPE html>
<html>
<head>
  <meta charset="utf-8">
  <meta name="viewport" content="width=device-width">
  <title>JavaScript program to check whether a string starts with 'Java' and false otherwise.</title>
</head>
<body>
</body>
</html>

JavaScript Code:

function start_spec_str(str)
{
  if (str.length < 4)
  {
    return false;
  }
  front = str.substring(0, 4);
  if (front == 'Java') 
  {
    return true;
  }
   else 
   {
    return false;
  }
}

console.log(start_spec_str("JavaScript"));
console.log(start_spec_str("Java"));
console.log(start_spec_str("Python"));

Sample Output:

true
true
false

Flowchart:

Flowchart: JavaScript - Check if a string starts with 'Java' and false otherwise

ES6 Version:

function start_spec_str(str)
{
  if (str.length < 4)
  {
    return false;
  }
  front = str.substring(0, 4);
  if (front == 'Java') 
  {
    return true;
  }
   else 
   {
    return false;
  }
}

console.log(start_spec_str("JavaScript"));
console.log(start_spec_str("Java"));
console.log(start_spec_str("Python"));

Live Demo:

See the Pen JavaScript: check if a string starts with Java -basic- ex-27 by w3resource (@w3resource) on CodePen.


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Previous: Write a JavaScript program to create a new string from a given string taking the last 3 characters and added at both the front and back.
Next: Write a JavaScript program to check if two given integer values are in the range 50..99 .

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JavaScript: Tips of the Day

Returns the sum of the powers of all the numbers from start to end (both inclusive)

Example:

const sumPower = (end, power = 2, start = 1) =>
  Array(end + 1 - start)
    .fill(0)
    .map((x, i) => (i + start) ** power)
    .reduce((a, b) => a + b, 0);
console.log(sumPower(10)); // 385
console.log(sumPower(10, 3)); // 3025
console.log(sumPower(10, 3, 5)); // 2925 

Output:

385
3025
2925