How do you compare the similarity of two colors?

Let’s say I have two colors, if I have a hexadecimal color value

var str1 = “#aabbcc”;

/ var reg1 = {1, 2}) (\ w/g;

var rs1 = str1.match(reg1);

var r1 = parseInt(“0x”+rs1[0]);

var g1 = parseInt(“0x”+rs1[1]);

var b1 = parseInt(“0x”+rs1[2]);

var str2= “#aabbcc”;

/ var reg2 = {1, 2}) (\ w/g;

var rs2 = str2.match(reg2);

var r2 = parseInt(“0x”+rs2[0]);

var g2 = parseInt(“0x”+rs2[1]);

var b2 = parseInt(“0x”+rs2[2]);

Then for the two colors, you can use distance Math.sqrt((R1-R2)*(R1-R2)+(G1-G2)*(G1-G2)+(B1-B2)*(b1-B2)) for comparison, and close distances are similar.