# Using JavaScript Logical Operators in ColdFusion 8

## by Simon. Average Reading Time: about a minute.

Following on from my posts on Arithmetic and Assignment operators, Logical operators are typically used with Boolean (logical) values; when they are, they return a Boolean value. However, the && and || operators actually return the value of one of the specified operands, so if these operators are used with non-Boolean values, they may return a non-Boolean value.

The logical operators are described in the following table:

Operator | Usage | Description |
---|---|---|

Logical AND (`&&` ) |
`expr1 && expr2` |
Returns `expr1` if it can be converted to false; otherwise, returns `expr2` . Thus, when used with Boolean values, `&&` returns true if both operands are true; otherwise, returns false. |

Logical OR (`||` ) |
`expr1 || expr2` |
Returns `expr1` if it can be converted to true; otherwise, returns `expr2` . Thus, when used with Boolean values, `||` returns true if either operand is true; if both are false, returns false. |

Logical NOT (`!` ) |
`!expr` |
Returns false if its single operand can be converted to true; otherwise, returns true. |

Using ColdFusion, the Logical operators can be expressed as follows:

**Logical AND**

In the below example, both operands, `x`

and `y`

, return true, therefore `myVariable`

is set to `true`

within the logical statement.

<cfscript> x = 9; y = 2; myVariable = false; if (x < 10 && y > 1) { myVariable = true; } </cfscript> |

**Logical OR**

In the below example, neither `x`

equals 10 nor `y`

equals 1, therefore the first part of the logical statement is not resolved. Instead, the `else`

statement is processed, assigning the boolean value `false`

to the variable `myVariable`

.

<cfscript> x = 9; y = 2; if (x == 10 || y == 1) { myVariable = true; } else { myVariable = false; } </cfscript> |

**Logical NOT**

In the below example, `x`

does not equal `y`

. Ordinarily this would result in the logical statement being evaluated, however, a logical negation has been applied to the beginning of the expression to be evaluated, therefore the variable `myVariable`

is assigned the boolean value `true`

.

<cfscript> x = 9; y = 2; myVariable = false; if (!x==y) { myVariable = true; } </cfscript> |