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Boolean

A Boolean value is either 'true' or 'false'. A Boolean variable can be initialized with a primitive Boolean value or a Boolean object.

The following all evaluate to 'false': false, 0,-0, null, undefined, NaN, “”, document.all

All other values evaluate to 'true'.

Do not confuse the primitive Boolean values 'true' and 'false' with a Boolean object.


RESETRUNFULL
<!DOCTYPE html><html><body><script>

var a = new Boolean(false);var b = false;if (a) console.log("a"); // loggedif (b) console.log("b"); // not loggedif (!0) console.log("!0");  // loggedif ("0") console.log("0");  // loggedif ([]) console.log("[]");  // loggedif ({}) console.log("{}");  // loggedif (document.all) console.log("document.all"); // not logged

</script></body><html>
This roughly converts a string to a Boolean primitive.
String(s).toLowerCase() == 'true'