Comparison operators

The other type of operators available in JavaScript are comparison operators . They are used to make assertions about the equality of two values (see Table 26-1).

Table 26-1. Comparison operators for equality




Greater than


Less than


Equal to


Not equal to


Greater than or equal to


Less than or equal to

There are also comparison operators that are used to assert identity (see Table 26-2).

Table 26-2. Comparison operators for identity




Identical to


Not identical to

To understand what identity is, take a look at two variables:

    var bool = true;
    var num  = 1;

bool is true, which is a Boolean value, and num is 1, a numeric value. If you recall back to the discussion of Booleans, however, you may recall that 1 and 0 are aliases for true and false, respectively. Therefore:

    bool == num;  /* bool is equal to num -or-
                     true and 1 are equal */

An identity-check, however, allows you to tell the two apart:

    bool !== num; /* bool is not identical to num -or-
                     true is not identical to 1 */

and that is why identity comparison operators are nice to have in your toolbox.

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