Conditional Operator (?:)
The 7: is the conditional operator in JavaScript, which requires three operands, hence it is called the ternary operator.
The syntax is:
var variablename=(condition) 7 valuel : value2;
In the syntax condition may be relational expression or logical expression. First condition will be evaluated, if the condition returns true then the value of the left side of the colon is assigned to the variable otherwise the value of the right side of the colon will be assigned the variable. For example,
var result=(10 > 15) ? 100 : 150;
In the above example, since the conditlon returns false the value 150 will be assigned to result.
HTML CODE:
< Html >
< Head >
< Title >Demo Program - To test Conditional 
Operator in JavaScript < /Title >
< /Head >
< Body >
< script language="javascript" type="text/
javascript" >
var valuel = 522, value2=150, value3;
value3=(valuel document.write("< br > The Value of Datal =
"+value3);
< /script >
< /Body >
< /Html >

Relational or Comparison Operators:
Relational operators are also called as Comparison operators, they compares two values and the result is true or false. Javascnpt provides a rich set of relational operators including = = (equal to), != (not equal to), < (less than), > (greater than), < = (less than or equal to), and > = (greater than or equal to). Using a relational operator in an expression causes the expression to evaluate as true if the condition holds or false if otherwise.

HTMLCODE: 
< Html >
< Head >
< Title >Demo Program - To test
Relational (Comparison) Operators in JavaScript
< /Title > 
< /Head >
< Body >
< script language="javascript" type="text!
javascript" >
var valuel = 522, value2=lO;
document. write(" < br > Data1 :
"+valuel);
document.wrlte("< br >Data2 :
"+value2);
document. write("< br > < br> Whether
Datal = Data2 : "+(valuel==value2));
document. write(" < br > Whether Data1
< Data2 : "+(valuel document. write(" < br > Whether Data1
> Data2 : "+(valuel > value2));
document. write(" <  br > Whether Datal
< = Data2 : "+(valuel < =value2));
document. write(" < br > Whether Data1
> = Data2 : "+(valuel > =value2));
document.write("< br > Whether Datal
!= Data2 : "+(valuel!=value2));
< /script >
< /Body >
< /Html >

The < SCRIPT > tag takes two important attributes -
(i) Language:
This attribute specifies that the scripting language. Typically, its value will be javascript. Although recent versions of HTML (Extensible HyperText Markup Language - XHTML, its successor) have phased out the use of this attribute is optional.
(ii) Type:
This attribute is used to indicate the scripting language and its value should be set to "text / javascript".

The strict rules are as follows:
(i) For && (AND) the result is false if the first operand is false; otherwise, the result is the Boolean value of the second operand.
(ii) For || (OR) the result is true if the first operand is true; otherwise, the result is the Boolean value of the second operand.
(iii) For! (NOT) the result is true if the operand is false; otherwise, the result is true.

The syntax of confirm dialog box is
confirm ("message ");
(or)
window.confirm (" message ");
Example:
confirm (" Hai Do you want to continue: ");
(or)
window.confirm(" Hai Do you want to continue: ");