- Greater/less than: a > b, a < b.
- Greater/less than or equals: a >= b, a <= b.
- Equals: a == b, please note the double equality sign == means the equality test, while a single one a = b means an assignment.
All comparison operators return a Boolean value:
- true – means “yes”, “correct” or “the truth”.
- false – means “no”, “wrong” or “not the truth”.
alert( 2 > 1 ); // true (correct)
alert( 2 == 1 ); // false (wrong)
alert( 2 != 1 ); // true (correct)
A comparison result can be assigned to a variable, just like any value:
let result = 5 > 4; // assign the result of the comparison
alert( result ); // true
In other words, strings are compared letter-by-letter.
alert( 'Z' > 'A' ); // true
alert( 'Glow' > 'Glee' ); // true
alert( 'Bee' > 'Be' ); // true
The algorithm to compare two strings is simple:
- Compare the first character of both strings.
- If the first character from the first string is greater (or less) than the other string’s, then the first string is greater (or less) than the second.
- Otherwise, if both strings’ first characters are the same, compare the second characters the same way.
- Repeat until the end of either string.
- If both strings end at the same length, then they are equal. Otherwise, the longer string is greater.
In the first example above, the comparison 'Z' > 'A' gets to a result at the first step.
The second comparison 'Glow' and 'Glee' needs more steps as strings are compared character-by-character:
- G is the same as G.
- l is the same as l.
- o is greater than e. Stop here. The first string is greater.