title: Checkbox value only when checked
body: <p>I'm trying to get the checkbox output to a variable x only when checked. Now it passes the value of checkbox even unchecked</p>
  <pre><code> function myFunction(){
          
       var  x  =parseInt(document.getElementById('cough').value)+
       parseInt(document.getElementById('cold').value)+ 
       parseInt(document.getElementById('fever').value) + 
       parseInt(document.getElementById('breathlessness').value) +
       parseInt(document.getElementById('loss of senses').value) + 
       parseInt(document.getElementById('sore throat').value) +
       parseInt(document.getElementById('none').value) +
       parseInt(document.getElementById('diabeties').value)+
       parseInt(document.getElementById('heart disorder').value) +
       parseInt(document.getElementById('lung disorder').value)+
       parseInt(document.getElementById('kidney disorder').value) + 
       parseInt(document.getElementById('hypertension').value) + 
       parseInt(document.getElementById('no disorder').value);
          
            console.log(x)
      }
  </code></pre>
  <p>I need to get these values only when checked</p>