Javascript that uses substring to split user input into two textareas depending on multiple If statement it only considers one if statement

i am kind of new to it all but i have an input field where the user would input a string and i need it to come out split in the right final field depending on numerical and nonnumerical part of the string and no matter what i do it at runtime it only goes through the first IF statement regardless of the length which is my IF statement criteria

<pre>

<p>Click the button to extract characters from the string.</p>

<p id="demo1"></p>
<form>

    <input id="userInput"><br>
    <label> Non Numeric</label><textarea id="nonNumeric"> </textarea>
    <label> Numeric</label><textarea id="numeric"> </textarea> <br>
    <label> Numeric Result</label><textarea id="numericResult"> </textarea>
</form>
<button onclick="seventeenDigitChasSearch()">Try it</button>

</pre> 

        <script>
    function seventeenDigitChasSearch() {
            var str =   document.getElementById("userInput").value ;
            var nonNumeric = str.substring(0, 14); //checks between index 0 and 13
            var numeric = str.substring(14, 17);  ////checks between index 14 and 17
     
        document.getElementById("nonNumeric").innerHTML = nonNumeric;
        document.getElementById("numeric").innerHTML = numeric;
      //convert the numeric number to an int value before evaluating it
            intNumeric =parseInt(numeric) ;
    
        if (intNumeric.toString().length = 17) {
    
            nonNumeric = str.substring(0, 14);
            numeric = str.substring(14, 17);
            document.getElementById("nonNumeric").innerHTML = nonNumeric;
            document.getElementById("numeric").innerHTML = numeric;
            document.getElementById("numericResult").innerHTML = "Yaay value is  within our of preferred";
            }
    
        else if (intNumeric.toString().length = 10) {
    
            
            numeric = str.substring(0, 10);
            document.getElementById("nonNumeric").innerHTML = "none";
            document.getElementById("numeric").innerHTML = numeric;
            document.getElementById("numericResult").innerHTML = "10 Range";
    
        }
          else if (intNumeric == null) 
    
          {
             document.getElementById("numericResult").innerHTML = "Faulty out of ranged numbers";
          }
    
    
    } ```