Properties
Methods
|
Description
|
infinity
|
A numeric value that represents positive/negative
infinity.
Example:
var x =
1.7976931348623157E+10308; // Infinity
var y =
-1.7976931348623157E+10308;// -Infinity
|
NaN
|
"Not-a-Number" value.
Example:
var a =
isNaN(123); //false
var b =
isNaN(-1.23); //false
var c =
isNaN(5-2); //false
var d =
isNaN(0); //false
var e =
isNaN("Hello"); //true
var f =
isNaN("2005/12/12"); //true
var g =
isNaN(); //true
var h =
isNaN('45'); //false
|
undefined
|
Indicates that a variable has not been assigned a
value.
Example:
var x;
if
(x===undefined) //or x==undefined
{
txt="x is undefined";
}
else
{
txt="x is is defined";
}
alert(txt); //returns: x is undefined
var x;
if (x===””) //or x==””
{
txt="x is undefined";
}
else
{
txt="x is is defined";
}
alert(txt); //returns: x is defined
|
JavaScript Global Functions
Methods
Methods
|
Description
|
decodeURI()
|
Encodes
a URI.
|
|
|
Decodes
a URI component.
|
encodeURI()
|
Encodes a URI.
This function encodes special characters, except: , / ? : @ & = + $ #
(Use encodeURIComponent()
to encode these characters).
var uri =
"my test.asp?name=ståle&car=saab";
var res =
encodeURI(uri);
alert(res);// my%20test.asp?name=st%C3%A5le&car=saab
|
encodeURIComponent()
|
Encodes
a URI component.
var uri =
"http://w3schools.com/my test.asp?name=ståle&car=saab";
var res =
encodeURIComponent(uri);
alert(res);
//http%3A%2F%2Fw3schools.com%2Fmy%20test.asp%3Fname%3Dst%C3%A5le%26car%3Dsaab
|
eval()
|
Evaluates
a string and executes it as if it was script code.
Example:
var x = 10;
var y = 20;
var a =
eval("x*y"); // 200
var b =
eval("2+2"); // 4
var c =
eval("x+17"); // 27
|
isFinite()
|
Determines
whether a value is a finite, legal number.
Example:
var a = isFinite
(123); // true
var b = isFinite
(-1.23); //
true
var c = isFinite
(5-2); //
true
var d = isFinite
(0); //
true
var e = isFinite
("Hello"); // false
var f = isFinite
("2005/12/12"); //false
var g = isFinite
(); //false
var h = isFinite
('45'); //true
var g =
isFinite(false); //true
var h =
isFinite(true); //true
|
isNaN()
|
Determines
whether a value is an illegal number.
Example:
var a =
isNaN(123); //false
var b =
isNaN(-1.23); //false
var c =
isNaN(5-2); //false
var d =
isNaN(0); //false
var e =
isNaN("Hello"); //true
var f =
isNaN("2005/12/12"); //true
var g =
isNaN(); //true
var h =
isNaN('45'); //false
|
Number()
|
Converts
an object's value to a number.
Example:
var test1 =
new Boolean(true);
var test2 =
new Boolean(false);
var test3 =
new Date();
var test4 =
new String("999");
var test5 =
new String("999 888");
var a =
Number(test1); //1
var b= Number(test2); //0
var c =
Number(test3); // 1388144600499
var d =
Number(test4); // 999
var e= Number(test5); // NaN
|
parseFloat()
|
Parses
a string and returns a floating point number.
Example:
var a =
parseFloat("10"); //10
var b =
parseFloat("10.00"); //10
var c =
parseFloat("10.33"); //10.33
var d =
parseFloat("34 45 66"); //34
var e =
parseFloat(" 60 "); //60
var f =
parseFloat("40 years"); //40
var g =
parseFloat("He was 40"); //NaN
|
parseInt()
|
Parses
a string and returns an integer.
Example:
var a =
parseInt("10"); //10
var b =
parseInt("10.00"); //10
var c =
parseInt("10.33"); //10
var d =
parseInt("34 45 66"); //34
var e =
parseInt(" 60 ");
//60
var f =
parseInt("40 years"); //40
var g =
parseInt("He was 40"); //
NaN
var h =
parseInt("10",10); / / 10
var i =
parseInt("010"); // 10
var j =
parseInt("10",8); //
8
var k = parseInt("0x10"); // 16
var l =
parseInt("10",16); //
16
|
String()
|
Converts
an object's value to a string.
Example:
var test1 =
new Boolean(1);
var test2 =
new Boolean(0);
var test3 =
new Boolean(true);
var test4 =
new Boolean(false);
var test5 =
new Date();
var test6 =
new String("999 888");
var test7 =
12345;
var a = String
(test1); // true
var b= String (test2); // false
var c = String
(test3); // true
var d = String
(test4); // false
var e= String (test5); // Fri Dec 27 2013
17:28:40 GMT+0530 (India Standard Time)
var f= String (test5); // 999 888
var g= String (test5); // 12345
|
escape()
|
Deprecated in
version 1.5. Use encodeURI()
or encodeURIComponent()
instead.
|
unescape()
|
Deprecated in
version 1.5. Use decodeURI()
or decodeURIComponent()
instead.
|
Properties