JSFiddle - React, Tailwind, and code Playground

HTML

<select id="zivila1">
<option value="0,0,0,0">Izberite živilo</option>
<option value="110,1.24,0,23.09">Piščanja prsa</option>
<option value="18,0.2,3.92,0.88">Paradižnik</option>
<option value="374,1.04,80.43,8.11">Riž</option>
</select>
<select id="kolicina1">
<option value="1">100g</option>
<option value="2">200g</option>
<option value="3">300g</option>
</select>
<br>
<select id="zivila2">
<option value="0,0,0,0">Izberite živilo</option>
<option value="110,1.24,0,23.09">Piščanja prsa</option>
<option value="18,0.2,3.92,0.88">Paradižnik</option>
<option value="374,1.04,80.43,8.11">Riž</option>
</select>
<select id="kolicina2">
<option value="1">100g</option>
<option value="2">200g</option>
<option value="3">300g</option>
</select>
<br>
<select id="zivila3">
<option value="0,0,0,0">Izberite živilo</option>
<option value="110,1.24,0,23.09">Piščanja prsa</option>
<option value="18,0.2,3.92,0.88">Paradižnik</option>
<option value="374,1.04,80.43,8.11">Riž</option>
</select>
<select id="kolicina3">
<option value="1">100g</option>
<option value="2">200g</option>
<option value="3">300g</option>
</select>
<br>
<button>
Izračunaj
</button>

<p id="kalorije">

</p>
<p id="mascobe">

</p>
<p id="oh">

</p>
<p id="beljakovine">

</p>

JavaScript

$('button').click(function()
{
//PRVO ŽIVILO
var kolicina1=$("#kolicina1").val();
var zivilo1=$("#zivila1" ).val();
var res1 = zivilo1.split(",");

//DRUGO ŽIVILO
var kolicina2=$("#kolicina2").val();
var zivilo2=$("#zivila2" ).val();
var res2 = zivilo2.split(",");

//TRETJE ŽIVILO
var kolicina3=$("#kolicina3").val();
var zivilo3=$("#zivila3" ).val();
var res3 = zivilo3.split(",");

var sumKalorije=0;
var sumMascobe=0;
var sumOh=0;
var sumBeljakovine=0;

sumKalorije=(res1[0]*kolicina1)+(res2[0]*kolicina2)+(res3[0]*kolicina3);
sumMascobe=(res1[1]*kolicina1)+(res2[1]*kolicina2)+(res3[1]*kolicina3);
sumOh=(res1[2]*kolicina1)+(res2[2]*kolicina2)+(res3[2]*kolicina3);
sumBeljakovine=(res1[3]*kolicina1)+(res2[3]*kolicina2)+(res3[3]*kolicina3);

$('#kalorije').text("Kalorije: "+sumKalorije+"kcal");
$('#mascobe').text("Maščobe: "+sumMascobe+"g");
$('#oh').text("Ogljikovi hidrati: "+sumOh+"g");
$('#beljakovine').text("Beljakovine: "+sumBeljakovine+"g");
})