Skip to content
Related Articles

Related Articles

Improve Article
Save Article
Like Article

JavaScript SyntaxError – Test for equality (==) mistyped as assignment (=)?

  • Last Updated : 19 Aug, 2020

This JavaScript warning test for equality (==) mistyped as assignment (=)? occurs if by assignment (=) is used in place of equality (==).

Message:

Warning: SyntaxError: test for equality (==) mistyped as assignment (=)?

Error Type:

SyntaxError: Warning which is reported only if 
javascript.options.strict preference is set to true.

Cause of error: There is an assignment (=) used in place of equality (==) in the code. 

Example 1: In this example, the ‘=’ is used in place of ‘==’. So the error has occurred.

HTML




<script>
if (a = b) { // Error here
  // do something
}
</script>

Output:

Warning: SyntaxError: test for equality (==) 
mistyped as assignment (=)?

Example 2:  In this example, the ‘=’ is used in place of ‘==’. So the error has occurred.

HTML




<script>
    var a = 5;
    var b = 4;
    var c = 5;
    if (b = c) {
      // do something
    } else if (a = c) {
      // do something
    }
</script>

Output:

Warning: SyntaxError: test for equality (==) 
mistyped as assignment (=)?

Hey geek! The constant emerging technologies in the world of web development always keeps the excitement for this subject through the roof. But before you tackle the big projects, we suggest you start by learning the basics. Kickstart your web development journey by learning JS concepts with our JavaScript Course. Now at it's lowest price ever!

My Personal Notes arrow_drop_up
Recommended Articles
Page :

Start Your Coding Journey Now!