I Read using QuerySelectall.. how to write in innerhtml of these read tags?

Question

I have degrees in Celsius switched them to Fahrenheit and cannot write them back to page.. picked them up with this statement

temp = document.querySelectorAll(".mylist span");
        x=[]
        for (let i = 0; i < temp.length; i++) {
            temp[i].style.backgroundColor = "red";
            x[i] = Number(temp[i].innerHTML);

Cannot write them back same way... Does not work

Answer 1

You need to set the innerHTML/textContent of the element with the new value.

const spans = document.querySelectorAll('#mylist span');

function CToF(v) {
  return v * 9/5 + 32;
}

setTimeout(() => {
  spans.forEach(span => {
    const { textContent } = span;
    span.classList.add('red');
    span.textContent = CToF(textContent);
  });
}, 2000);

.red { color: red; }

<div id="mylist">
  <span>10</span>
  <span>40</span>
  <span>90</span>
</div>