检查输入值是否为回文的 Function 始终返回 true

Question

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>

Answer 1

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.

Answer 2

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.