See The Code

Gets the range of numbers within 50,000

function getRange(start, end){
  if (end > 50_000) {
  alert("End Number Is To High, Cannot Exceed 50,000");
  return;
  }

  let numArray = [];
  for (let index = start; index <= end; index++) { 
  numArray.push(index);
  }
  return numArray;
}

Take user input and print numbers to the page

function printNumbers(){
  let start = parseInt(document.getElementById("numOne").value);
  let end = parseInt(document.getElementById("numTwo").value); 

  let numbers = getRange(start, end);

  displayData(numbers);
}

Display the numbers on the page

function displayData(numbers){
  const rowTemplate = document.getElementById("Data-Template");
  const resultsBody = document.getElementById("resultsBody");
  let colCount = rowTemplate.content.cloneNode(true).querySelectorAll("td").length;
  // ImportNode
  // Clear the table
  resultsBody.innerHTML = "";

  // Loop over every element in the numbers array
  // Get the values and write them to the page
  for (let rowIndex = 0; rowIndex < numbers.length; rowIndex +=colCount) { 
    let dataRow=rowTemplate.content.cloneNode(true); 
    let cols=dataRow.querySelectorAll("td"); // Returns array of td elements
    findFizzBuzz(numbers, cols, rowIndex) // Add the row to the page resultsBody.appendChild(dataRow); } 
}

Filter for multiples of 3, 5, or both and add a CSS class to format text and font color

function findFizzBuzz(numbers, cols, rowIndex){
  for (let colIndex = 0; colIndex < cols.length; colIndex++) { 
    let value=numbers[rowIndex + colIndex]; 
    if (typeof value==="undefined" ) {
       value="" ;
       }
        else { if (value % 3==0 && value % 5==0) { 
          value=`FizzBuzz`;
    cols[colIndex].classList.add("fizzBuzz"); 
  } else  { 
    if(value % 2==0){ 
       cols[colIndex].classList.add("boldIt");
       }
    if(value % 3==0){ 
      value=`Fizz`; cols[colIndex].classList.add("fizz"); 
    }
     if(value % 5==0){ 
       value=`Buzz`;
    cols[colIndex].classList.add("buzz");
   } 
  } 
} // Note:  use textContent to set content
    cols[colIndex].textContent = value;
    }
  }

Full Source Code Below

          // Take user input and print numbers to the page
          function printNumbers(){
          let start = parseInt(document.getElementById("numOne").value);
          let end = parseInt(document.getElementById("numTwo").value);

          let numbers = getRange(start, end);

          displayData(numbers);
          }

          // Gets the range of numbers
          function getRange(start, end){
          if (end > 50_000) {
          alert("End Number Is To High, Cannot Exceed 50,000");
          return;
          }

          let newArray = [];
          for (let index = start; index <= end; index++) { newArray.push(getFizzBuzz(index)); } return newArray; }
            function getFizzBuzz(num) { let multiple1=document.getElementById("mulOne").value; let
            multiple2=document.getElementById("mulTwo").value; if (num % multiple1==0 && num % multiple2==0) { return
            `FizzBuzz`; } else { if (num % multiple1==0) { return `Fizz`; } if (num % multiple2==0) { return `Buzz`; } }
            return num; } // Display the numbers on the page function displayData(numbers){ const
            rowTemplate=document.getElementById("Data-Template"); const
            resultsBody=document.getElementById("resultsBody"); // Clones a template, then filters for all 
            elements, then gets the length
            let colCount = rowTemplate.content.cloneNode(true).querySelectorAll("td").length;
            resultsBody.innerHTML = "";

            // Loop over every element in the numbers array
            // Get the values and write them to the page
            for (let rowIndex = 0; rowIndex < numbers.length; rowIndex +=colCount) { let
              dataRow=rowTemplate.content.cloneNode(true); let cols=dataRow.querySelectorAll("td"); // Returns array of
              td elements for (let colIndex=0; colIndex < cols.length; colIndex++) { let value=numbers[rowIndex +
              colIndex]; formatFizzBuzz(value, cols, colIndex); // Add the row to the page
              resultsBody.appendChild(dataRow); } } } function formatFizzBuzz(value, cols, colIndex){ if (typeof
              value==="undefined" ) { value="" ; }else { if (value==`FizzBuzz`) {
              cols[colIndex].classList.add("fizzBuzz"); } if (value==`Fizz`) { cols[colIndex].classList.add("fizz"); }
              if (value==`Buzz`) { cols[colIndex].classList.add("buzz"); } } // Note:  use textContent to set
              content
              cols[colIndex].textContent = value;
              }


              function changeValue() {
              let multiple1 = document.getElementById("mulOne").value;
              let multiple2 = document.getElementById("mulTwo").value;
              document.getElementById("mulFizz").textContent = `${multiple1} = `;
              document.getElementById("mulBuzz").textContent = `${multiple2} = `;
              document.getElementById("mulFizzBuzz").textContent = `${multiple1} & ${multiple2} = `;
              }