JavaScript
Data Types
·
JavaScript variables can also hold other types of data, like
text values (person="Kiran Kumar").
·
In JavaScript a text like "Kiran Kumar" is called a
string.
·
When you assign a text value to a variable, put double or single
quotes around the value.
·
When you assign a numeric value to a variable, do not put quotes
around the value. If you put quotes around a numeric value, it will be treated
as text.
Types of Datatypes:
1.
Primitive Data types
2.
User Defined Datatypes://not available in javascript
1.
Primitive
Datatypes:
1.
Numbers
2.
Strings
3.
Boolean
//we have so many datatypes but we consider
these 3 datatypes
Example:
var pi=3.14;
var s="Rama Rao";
var a='Hey!';
var s="Rama Rao";
var a='Hey!';
JavaScript
Has Dynamic Types
JavaScript has dynamic types. This means that
the same variable can be used as different types:
Example
var
x;
// Now x is undefined
var x = 5; // Now x is a Number
var x = "Ram"; // Now x is a String
var x = 5; // Now x is a Number
var x = "Ram"; // Now x is a String
JavaScript
Strings
·
A string is a variable which stores a series of characters like
"John Doe".
·
A string can be any text inside quotes. You can use single or
double quotes:
·
You can use quotes inside a string, as long as they don't match
the quotes surrounding the string:
Example
<!DOCTYPE
html>
<html>
<body>
<script>
var movie="evadu";
var movie2='sri ram';
document.write(movie + "<br>")
document.write(movie2 + "<br>")
</script>
</body>
<!--http://improvejavascript.blogspot.in/ -->
</html>
JavaScript
Numbers
JavaScript has only one type of numbers.
Numbers can be written with, or without decimals:
Example
var
x1=34.00; // Written with decimals
var x2=34; // Written without decimals
var x2=34; // Written without decimals
Extra large or extra small numbers can be
written with scientific (exponential) notation:
Example
var
y=123e5; // 12300000
var z=123e-5; // 0.00123
var z=123e-5; // 0.00123
<!DOCTYPE html>
<html>
<body>
<script>
var x1=34.00;
var x2=34;
var y=123e5;
var z=123e-5;
document.write(x1 + "<br>")
document.write(x2 + "<br>")
document.write(y + "<br>")
document.write(z + "<br>")
</script>
</body>
<!-- http://improvejavascript.blogspot.in/ -->
</html>
//output
JavaScript
Booleans
Booleans can only have two values: true or
false.
var x=true;
var y=false;
var y=false;
TYPE CASTING:
Def: converting from one data type to another data type is
called type casting.
In JavaScript variables are automatically type
casted(implicitly) based on the literal values that are assigned to it from
time to time.
Ex:
Var a=”total”;
Var b=1000;
Var c=a+b;
Document.write(c);//result is “total 1000”
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