Relational operator <,<=,>,>= is used to compare strings

Using a relational operator on two strings, many people think that less than means "in alphabetical order", greater than "in alphabetical order", but that is not the case. For a string, the code for each character in the first string is compared to the code for the character at the corresponding position in the second string. When this comparison operation is completed, a Boolean value is returned. The problem is that the code for uppercase letters is smaller than the lowercase code, which means you might encounter the following scenario:

var bresult = "Brick" < "alpha";

alert (bresult);//output:true;

In this example, the string "Brick" is less than the string "alpha" because the character code of the letter B is 66, and the character code for the letter A is 97. To force the results to be obtained alphabetically, you must convert the two operands to the same case (all uppercase or all lowercase) and then compare the rows. For example:

var bresult = "Brick". toLowerCase () < "Alpha". toLowerCase ();

alert (bresult);//Output:false;

Another tricky situation occurs when comparing numbers in the form of two strings, for example:

var bresult= "All" < "3";

alert (bresult);//output:true;

Because both operations are strings, their character code is compared (the character code for "2" is 50; the character code for "3" is 51) so the output is true;

However, it is interesting to change one of the operators in the above example to a number, for example:

var bresult= "3" <;

alert (bresult);//output:false;

If a string number and a number are properly compared, ECMAScript converts the number of the string to a number and then the size of the comparison.

But what if the string cannot be converted to a number?

var bresult= "a" < 3;

alert (bresult);//output:false;

The letter A cannot be swapped for meaningful numbers, but calling the parseint () method returns Nan, and according to the rules, any relational operation that contains Nan will return false, so this code also outputs false;

var bresult= "a" < 3;

alert (bresult);//output:false;

Typically, a greater than or equal operation must return TRUE if the two values of the less-than operation return FALSE, but this is not the case if a number is Nan.

Relational operator <,<=,>,>= is used to compare strings