> Object.prototype.toString.call(3) "[object Number]" > Object.prototype.toString.call(new Number(3)) "[object Number]"
var n1 = 0; var n2 = new Number(0); n1 == n2 // true n1 === n2 // false if (n1) { // Doesn't execute } if (n2) { // Does execute, because n2 is an object that is not null }
$(window).bind('beforeunload', function() { if(/Firefox[\/\s](\d+)/.test(navigator.userAgent) && new Number(RegExp.$1) >= 4) { if(confirm("Are you Sure do you want to leave?")) { history.go(); } else { window.setTimeout(function() { window.stop(); }, 1); } } else { return "Are you Sure do you want to leave?"; } });
typeof 50 === typeof new Number(50) //--> false; number != object
> typeof new Boolean(false) "object" > typeof new String("foo") "object" > typeof new Number(42) "object"
console.log(true instanceof Boolean); // false console.log(0 instanceof Number); // false console.log("" instanceof String); // false console.log(new Boolean(true) instanceof Boolean); // true console.log(new Number(0) instanceof Number); // true console.log(new String("") instanceof String); // true
console.log(typeof new Boolean(true)); // object console.log(typeof new Number(0)); // object console.log(typeof new String("")); // object
var num = new Number(14.12); console.log(num.toPrecision(2));//outputs 14 console.log(num.toPrecision(3));//outputs 14.1 console.log(num.toPrecision(4));//outputs 14.12 console.log(num.toPrecision(5));//outputs 14.120
var redir="main.html"; if (/MSIE (\d+\.\d+);/.test(navigator.userAgent)) { var ieversion=new Number(RegExp.$1); if (ieversion<=8) { redir = "ie.html"; } } window.location = redir;
var x = Number('09'); typeof x; // 'number' var x = new Number('09'); typeof x; // 'object' Number('1') === new Number('1'); // false
var num1 = new Number(3.141592); var num2 = num1.toFixed(); // 3 var num3 = num1.toFixed(2); // 3.14 var num4 = num1.toFixed(10); // 3.1415920000
var num = new Number(349); document.write("$" + num.toFixed(2));
var num1 = new Number(3.641592); var num2 = num1.toFixed(); // 4
>>> typeof("a") "string" >>> typeof(new String("a")) "object" >>> typeof(4) "number" >>> typeof(new Number(4)) "object"
var a=new Object() or var a=Object() or var a={} //Create object of type Object var a=new String() //Create object of type String var a=new Number() //Create object of type Number var a=new Boolean() //Create object of type Boolean var a=new Array() or var a=Array() or var a=[] //Create object of type Array var a=new RegExp() or var a=RegExp() //Create object of type RegExp var a=new UserDefinedFunction()
WritableWorkbook workbook = Workbook.createWorkbook(new File("output.xls")); WritableSheet sheet = workbook.createSheet("First Sheet", 0); Label label = new Label(0, 2, "A label record"); sheet.addCell(label); Number number = new Number(3, 4, 3.1459); sheet.addCell(number);
var that = new Number(0); // Now it's an object number function go(input) { input++; } go(that); that *= 1; // Now it's a literal number console.log(that); // 0