Possible Duplicate:   Javascript === vs == : Does it matter which “equal” operator I use?        What is the difference between == and === in JavaScript?  I have also seen != and !== operators.  Are there more such operators?...

I've been trying to understand the difference between JavaScript's comparison operators: identity and equality. From what I've read, if you check the equality of two objects using ==, JavaScript will try to figure out if they are the sa...

I've been reading Douglas Crockford's JavaScript: The Good Parts, and I came across this weird example that doesn't make sense to me:  '' == '0'           // false 0 == ''             // true 0 == '0'...

The code:  var num = 20;  if(num == "20") {     alert("It works"); } else {     alert("Not working"); }   The question:   In C programming we have a rule name data type promotion, where when there's a mix of data type (exa...

A few weeks ago, I have read this thread Is < faster than <=? about comparison operators in C. It was said that there is no difference in the performance between < and <= as they are interpreted as same/similar machine commands.  At the s...

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Ruby has something called a Combined Comparison or "Spaceship" Operator, it looks like this: <=>  It does the following:  a <=> b :=     if a < b then return -1     if a = b then return  0     if a > b then return  1   Credi...

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What am I missing here? This script looks right to me.   But for some reason when I send it a zipcode of 02897 (or anything that should be Rhode Island), it returns New Hampshire. Aside from political beliefs Javascript developers may have (sure most...

I have this output in the console:  console.log((!undefined)==(!false)) // true (fine) console.log((!!undefined)==(!!false)) // true (still fine)   As I know, !!x==x, isn't it?  console.log((undefined)==(false)) // false   Can anyone tell me why...