在 Javascript IF-ELSE 中，IF 语句不起作用

Question

I am trying to work on verifying OTP. Here I have two components that are:

1. Textbox which takes input of OTP. id="txtOTP"
2. An Status Line (here i have used <i> tag) that shows status of verified OTP. id="statusLine"

I am using JavaScript for this purpose.

function checkOTP() 
{
  var OTP = "1234";
  var txtOTP = document.getElementById('txtOTP');
  var statusLine = document.getElementById('statusLine');
  var myOTP = txtOTP.value;

  if (OTP.value == myOTP) 
 {
    console.log('Entered in Valid OTP');
    statusLine.style.display = "inline";
    statusLine.style.color = "green";
    statusLine.innerHTML = "OTP Verified, Generating Your Pass and Redirecting to the Next Page... ";
    console.log('Exit From Valid OTP');
    return true;
  } 
  else if (OTP.value != myOTP) 
  {
    console.log('Entered in Invalid OTP');
    statusLine.style.display = "inline";
    statusLine.style.color = "red";
    statusLine.innerHTML = "Invalid OTP. Please Try Again";
    console.log('Exit From Invalid OTP');
    return false;
  }
}

As Per my code it should go to the if's scope if OTP is correct, and it should go to the else's scope if OTP is wrong. However, it always goes to the else's scope even though I am writing the correct OTP in the textbox. I have even tried this code without using if with the else statement (like else if() { } ).

Answer 1

You need to either change myOTP to a number or use double equals:

var myOTP = parseInt(txtOTP.value);

Or:

if (OTP == myOTP) {...}

Also note that you don't need else if (...) - just use else {...} .

Answer 2

OTP is a Number but you check OTP.value in if/else if statements

function checkOTP()
            {
                var OTP = 1234;
                var txtOTP = document.getElementById('txtOTP');
                var statusLine = document.getElementById('statusLine');
                var myOTP = txtOTP.value;

                if(OTP === myOTP )
                {
                    console.log('Entered in Valid OTP');
                    statusLine.style.display = "inline";
                    statusLine.style.color = "green";
                    statusLine.innerHTML = "OTP Verified, Generating Your Pass and Redirecting to the Next Page... ";
                    console.log('Exit From Valid OTP');
                    return true;
                }
                else if(OTP != myOTP )
                {
                    console.log('Entered in Invalid OTP');
                    statusLine.style.display = "inline";
                    statusLine.style.color = "red";
                    statusLine.innerHTML = "Invalid OTP. Please Try Again";
                    console.log('Exit From Invalid OTP');
                    return false;
                }
            }

Answer 3

Here is a solution. Its based on the comments and previous answers:

function checkOTP() {
    var OTP = "1234";
    var txtOTP = document.getElementById('txtOTP');
    var statusLine = document.getElementById('statusLine');
    var myOTP = txtOTP.value;

    if (OTP == myOTP) {
        console.log('Entered in Valid OTP');
        statusLine.style.display = "inline";
        statusLine.style.color = "green";
        statusLine.innerHTML = "OTP Verified, Generating Your Pass and Redirecting to the Next Page... ";
        console.log('Exit From Valid OTP');
        return true;
    }  else {
        console.log('Entered in Invalid OTP');
        statusLine.style.display = "inline";
        statusLine.style.color = "red";
        statusLine.innerHTML = "Invalid OTP. Please Try Again";
        console.log('Exit From Invalid OTP');
        return false;
    }
}

You needed to write OTP instead of OTP.value and you don't need and else if for the opposite. Just else will do.

Answer 4

try adding a else statement after the else if since the syntax is :

if (condition1) {
  //  block of code to be executed if condition1 is true
} else if (condition2) {
  //  block of code to be executed if the condition1 is false and condition2 is true
} else {
  //  block of code to be executed if the condition1 is false and condition2 is false
}