swap 2 numbers without third variable

var swap = function (a, b) {
    var a, b;
    document.querySelector('.input').innerHTML = 'a = ' + a + '; b = ' + b;
    a = a + b;
    b = a - b;
    a = a - b;
    document.querySelector('.result').innerHTML = 'a = ' + a + '; b = ' + b;
}
 
swap(5, 10);

var swap = function (a, b) { var a, b; document.querySelector('.input').innerHTML = 'a = ' + a + '; b = ' + b; a = a + b; b = a - b; a = a - b; document.querySelector('.result').innerHTML = 'a = ' + a + '; b = ' + b; } swap(5, 10);

<h3>before swapping: <span class="input"></span></h3>
 
<h3>after swapping: <span class="result"></span></h3>
 
swapping algorithm:
<div>
    a = a + b;
    b = a - b;
    a = a - b;
</div>

<h3>before swapping: <span class="input"></span></h3> <h3>after swapping: <span class="result"></span></h3> swapping algorithm: <div> a = a + b; b = a - b; a = a - b; </div>