CODEWITHSUNDEEP
javascripthtml
Sergio De Crescenzo
Sergio De Crescenzo

Reputation: 75

Function that checks whether input value is palindrome or not always returns true

I'm trying to create a program that prints out if a word is a palindrome or not, but for some reason it doesn't work.

When I click the button it says that the word is palindrome even if it is not. I tried to replace the inputString with a variable and it works. So I think it's a problem of the line document.getElementById ("word").value.

var inputString = document.getElementById("word").value;
var textTrue = "It's a palindrome!";
var textFalse = "Sorry, that's not a palindrome.";

//function that return true if the word is palindrome and false if it is not
function isPalindrome(inStr) {
  for (let i = 0; i < inStr.length; i += 1) {
    if (inStr[i] !== inStr[inStr.length - 1 - i]) {
      return false;
    }
  }
  return true;
}
    
/* function that print "the word is palindrome" if the isPalindrome function returns true
or "the word is not palindrome" if the isPalindrome function returns false */
function clickFunction() {
  if (isPalindrome(inputString)) {
    console.log(textTrue);
  } else {
    console.log(textFalse);
  }
}
<header>
  <h1>PALINDROME WORD CHECKER</h1>
</header>

<input class="inputbox" type="word" id="word" placeholder="input">
<button onclick="clickFunction()"> Check! </button>
<script src="code.js"></script>

Upvotes: 0

Views: 180

Answers (2)

Paras Prajapati
Paras Prajapati

Reputation: 224

you can change your input type =" text"

<input class="inputbox" type="text" id="word" placeholder="input">

js file also

function clickFunction() {
var inputString = document.getElementById("word").value;
if (isPalindrome(inputString)) {
    console.log(textTrue);
} else {
    console.log(textFalse);
}

}

you get definitely result.

Upvotes: 1

px1mp
px1mp

Reputation: 5372

You have to read the content of inputString only after you fill in the text and click on your "Check" button. So You have to move the first line:

var inputString = document.getElementById("word").value;

into your function:

function clickFunction() {
    var inputString = document.getElementById("word").value;
    if (isPalindrome(inputString)) {
        console.log(textTrue);
    } else {
        console.log(textFalse);
    }
}

Otherwise, the inputString is only read when the page loads and never gets updated with the content of the input, and the textbox's initial value is "" (empty string), which is a palindrome.

Upvotes: 3

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