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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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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

Parameter's value

function getItems(fruitList, ...args, favoriteFruit) {
  return [...fruitList, ...args, favoriteFruit]
}

getItems(["banana", "apple"], "pear", "orange")

...args is a rest parameter. The rest parameter's value is an array containing all remaining arguments, and can only be the last parameter! In this example, the rest parameter was the second parameter. This is not possible, and will throw a syntax error.

function getItems(fruitList, favoriteFruit, ...args) {
  return [...fruitList, ...args, favoriteFruit];
}


getItems(['banana', 'apple'], 'pear', 'orange');
The above example works. This returns the array [ 'banana', 'apple', 'orange', 'pear' ].

Ref: https://bit.ly/3jFRBje