Array part 3

Accessing an Array



Attempting to access an index outside of the array, returns the value undefined.
var courses = new Array("HTML", "CSS", "JS");
document.write(courses[10]);
//Outputs "undefined"Try It Yourself

Our courses array has just 3 elements, so the 10th index, which is the 11th element, does not exist (is undefined).

Comments

Post a Comment

Popular posts from this blog

String Operators

Image
COURSES CODE PLAYGROUND DISCUSS TOP LEARNERS String Operators 39 1/1   String Operators The most useful operator for strings is  concatenation , represented by the + sign.  Concatenation can be used to build strings by joining together multiple strings, or by joining strings with other types:  var mystring1 = "I am learning "; var mystring2 = "JavaScript with SoloLearn."; document.write(mystring1 + mystring2); Try It Yourself The above example declares and initializes two  string  variables, and then concatenates them. Numbers in quotes are treated as strings: "42" is not the number 42, it is a  string that includes two characters, 4 and 2. What is the output of the following code: var x = "50"; var y = "100"; document.write(x+y); 50100 5000 Null 150
Read more

Introducing object part 3

Object Methods An  object   method   is a property that contains a  function definition . Use the following syntax to access an  object method . objectName.methodName() As you already know,  document.write() outputs data. The  write()  function is actually a  method  of the  document   object . document.write("This is some text"); Try It Yourself Methods are functions that are stored as  object  properties.
Read more

Associative Arrays part 2

Associative Arrays Remember that JavaScript  does not  support arrays with named indexes. In JavaScript, arrays always use numbered indexes. It is better to use an  object   when you want the index to be a  string  (text). Use an  array   when you want the index to be a  number . If you use a named index, JavaScript will redefine the  array  to a standard  object .
Read more