Javascript If/else style changing

i have a problem with simple if else statement that changes text color of a

element depending on a current color. I see why i get certain results but i can't seem to find a solution. Any help to newbie like me appreciated.

HTML <p id="demo">JavaScript can change the style of an HTML element.</p>

JS TRY 1

<script> 
var x = document.getElementById("demo");

    function one() {  

x.style.fontSize="16px";
x.style.color="black";}

function two() {

x.style.fontSize="16px";
x.style.color="red";}

function three(){

if(x.style.color="black") { two() }
else {one()
}
}
</script>` <button type="button" onclick="three()">Click Me!</button>

JS TRY 2

<script> 
var brojilo = 1 ;
function three(){ 
 var x = document.getElementById("demo");

function two() {

x.style.fontSize="18px";
x.style.color="red";}

function one() {  

x.style.fontSize="18px";
x.style.color="black";}

if (brojilo % 2 == 0)
{one()} 
else
{two()}

var brojilo = brojilo + 1 ;

}
</script><button type="button" onclick="three()">Click Me!</button>

JS TRY 3

<script> 
var b2 = 0 ;

function brojanje(){
var b2 = b2+1;}

function three(){ 
 var x = document.getElementById("demo");

function two() {

x.style.fontSize="18px";
x.style.color="red";}

vfunction one() {  

x.style.fontSize="18px";
x.style.color="black";}

if (b2 % 2 == 0)
{one()} 
else
{two()}
}
</script><button type="button" onclick="three(); brojanje ();">Click Me!</button>

Thanks in advance