Question

I saw this in code today and I am kind shocked that it does not produce an error

if($('.MyClass'))
{
  // do stuff here
}

So it is a jquery selector inside a if statement. According to firebug if the selector is not found it returns null. If it is found it returns the dom object.

So from what I can tell it always goes into the if statement but I am kind a more shocked that it does not error out.

If in C# you tried to just have an object or null in an if statement I don’t think it would compile.

I was expecting at least an error to show up in firebug.

Answer 1

It doesn’t error out because (I’m assuming, of course, that you mistyped your question and you have quotes around your class name like if($('.MyClass'))):

if(null){
    // Do something
}

Is valid syntax in JavaScript (although it may not do what you expect it to do).

JavaScript will try to cast null to a boolean value. When that cast happens, JavaScript specifies that the cast should return false.