jQuery/Javascript the comparison operators "===" and "=="

Question

in dreamweaver cc 2015, when i am using the comparison operators in jquery/javascript programming like:

 if(x == "")

DW shows an error that Expected === and instead saw ==. My question is that what is the difference between === and == ?. As i know in other languages like C# etc the === operator means that the comparison will check the Data Type of the value as well as the value. In javascript or jquery is there any problem if i use the == instead of === ? or still the result will be the same in jquery / javascript?

Answer 1

In Javascript, === do not try to coerce the type of the variables you are testing, while == will do its best to 'typecast' those variables if needed to compare them.

For instance 1 == '1' returns true, while 1 === '1' returns false since you are comparing a number to a string.

Lastly, jQuery and pure javascript both uses the same === and == operators. Hence, there will not be any difference between the two.

The MDN documentation is pretty good too.

Answer 2

The == operator will compare for equality after doing any necessary type conversions. The === operator will not do the conversion, so if two values are not the same type === will simply return false. Both are equally quick.
For more you can check this answer in stack oveflow
Which equals operator (== vs ===) should be used in JavaScript comparisons?

Answer 3

There is a slight difference between == and === operators. If you are using == that means you are comparing just values for example (5=='5') will return you true whereas first operand is integer and the second operand is string.Now considering the same example with === i.e (5==='5') will return you false because the '===' operator will check the value as well as type conversion and in this case integer cannot be equal to the string. Hope this helps you.