Two similar arrays produce falsity with == comparision? [duplicate]

This question already has an answer here:

• How to compare arrays in JavaScript? 30 answers

Lets take two arrays

var apple = [1,2,3];
var bracket = [1,2,3];

and a string cat here with the same contents as the initial 2 arrays with no difference except comma (,)

var cat = "1,2,3";

Now lets test the equality between the 2 arrays with the following code.

 if(apple == bracket){
        console.log("Both are equal");
    }
    else{
        console.log("Both are not equal");
 }

Everyone including me would have guessed it would print Both are equal.But the opposite is true.It prints Both are not equal.How is this possible.

Here is more surprice

if(apple == cat){
    console.log("Both are equal");
}
else{
    console.log("Both are not equal");
}

Here also the otherway the output comes,it would print Both are equal.