JavaScript relational (comparison) operators

Operators used for comparison are called as relational operators: less Than (<), greater than (>), less than or equal (<=), greater than or equal (>=), equal (= =), unequal (! =), congruent (identity) (= = =), not congruent (not identical) (!==)

As with other operators, you should follow the rules when the relational operators manipulate non-numeric values:
1. Two operands are numeric, then numerical comparison;
2. The two operands are all strings, then the character encoding values corresponding to two strings are compared;
3. The two operand has one value, then the other is converted to a numeric value, and then the numerical comparison is performed;
4. The two operands have one object, then the ValueOf () method or the ToString () method are called before the results are compared;

 　  varbox = 3 > 2;//true 　　 varbox = 3 > 22;//false 　　 varbox = ' 3 ' > 22;//false 　　 varbox = ' 3 ' > ' 22 ';//true compares the first character of a numeric string, where the first number of the first string is 3 greater than the first number 2 of the second string, so true 　　 varbox = ' A ' > ' B ';//false a=97,b=98 　　 varbox = ' A ' > ' B ';//true B=66,a is a 　　 varbox = 1 > {};//False if there is toString () or valueOf () returns the value of 1 > return number 　　 varbox = 1>{toString:function() {return2; }}//This compares the return value of the 1> object to 2, the result is false

Second, on equal and unequal comparisons, if the operand is a non-numeric value, follow the rules:
1. An operand is a Boolean value, then it is converted to a numeric value before comparison, and false turns into 0,true to 1;
2. An operand is a string, then the comparison is made before comparing it to a number;
3. An operand is an object, then the ValueOf () or toString () method is called before the comparison with the return value;
4. If no conversion is required, null and undefined are equal;
5. An operand is nan, then = = Returns false,!= True, and Nan is not equal to itself;
6. The two operands are objects, and if they are the same object, return True if they all point to the same object, or false otherwise.
7. Returns true for equal and all-unequal judgments, such as values and types, and returns false otherwise.

   varbox = 2 = = 2;//true 　　 varbox = ' 2 ' = = 2;//true, ' 2 ' will turn into a value of 2 　　 varbox =false= = 0;//True,false turns into a value of 0 . 　　 varbox = ' a ' = = = ' a ';//false, the converted encoding is not the same 　　 varbox = 2 = = {};//false, executing toString () or valueOf () will change 　　 varbox = 2 = = NaN;//false, as long as there is NaN, is false 　　 varbox = {} = = {};//false, compared to their address, each new created object has a different reference address 　　 varAge = {}; varHeight =Age ; varbox = age = = height;//true, the reference address is the same, so equal 　　 varbox = ' 2 ' = = = 2//false, both values and types must be equal 　　 varbox = 2!== 2//false, both values and types are equal

Third, special value comparison table

JavaScript relational (comparison) operators