Which of the following will correctly check if a variable is undefined in JavaScript?

Which 'if' statement is correctly used to get the size of both 'variable1' and 'variable2' objects? var variable1 = {'name':'theName', 'address':'theAddress','age': '18'} var variable2 = ['theName','theAddress','18']; variable1["name"] = "theName2"; variable1["name"] = "theName3"; variable1["name2"] = "theName4"; variable1["name2"] = "theName5"; Object.size = function(importer) { var exporter = 0, key; for (key in importer) { if (importer.hasOwnProperty(key)) exporter++; } return exporter; };

Which uses the 'with' statement in JavaScript correctly?

Which can be used for disabling the right click event in Internet Explorer?

Why does Google prepend while(1); to their JSON responses?

An HTML form contains 10 checkboxes all named 'chkItems'. Which JavaScript function can be used for checking all the checkboxes together?

What's the output? var str1 = 'Hi world'; var str = 'Apples are round, and apples are juicy'; var sliced = str.slice(5, -2); var text =`Apple \nJuice` var raw_text = String.raw`Apple \nJuice` console.log(str1.valueOf()); console.log(raw_text) console.log(sliced); console.log(text)

In relation to object oriented JavaScript, which are the correct attributes of the object properties?

While working with JavaScript Page Redirection, which is an invalid method of the window.location object?

Which javascript method can be used to create or modify the attribute properties

Which is not a valid JavaScript operator?