如何编写 javascript 错误以用逗号分隔输入并且输入不在换行符上

Question

I am trying to write an error on javascript. Firstly if the input text is not separated by a comma and then another error if each instance of the input text is not on a new line. What i have currently the error is being displayed even if the input is correct.

Here is the function:

function verify(){
    if(!document.getElementById('input-text').value.trim().length){
        alert("Cannot be empty. Enter the module names and marks separated by comma [put each module in a new line]");
    }else if(document.getElementById('input-text').value != input_text.match(/[^\r\n]+/g)){
        alert("Module names and marks must be seperated by a comma.");
    }
}

Where input-text is being defined

   Student Grade Checker App
    </div>
    <div>
        <textarea class="display-input" id="input-text" rows="5" cols="35" required minlength="2" placeholder="Enter the module names and marks separated by comma [put each module in a new line]" value="">Enter the module names and marks separated by comma [put each module in a new line]</textarea>
    </div>
    <div>
        <textarea class="display-output" id="output-text" rows="5" cols="35" readonly=1 placeholder="Results here..." value="">
        </textarea>
    </div>
    <div>
        <button class="sgcbutton-active" onclick="verify();getTotal();">Total Marks</button>
    </div>

Accepted input text

Programming,70
Data,60
Computing,40

Answer 1

I think the aim is to detect non-empty text that is non-empty, has commas, and every comma followed by a newline (that last bit is a guess, but its a sensible sounding thing for a text area for inputting a list.

function verify() {
  let input = document.getElementById('input-text').value;
  if (!input.trim()) {
    alert("Cannot be empty. Enter the module names and marks separated by comma [put each module in a new line]");
    return false;
  }
  let comps = input.split(',');
  // is it okay to have no commas? if not
  if (comps.length === 1) {
    alert("you need at least one comma, right?");
    return false;
  }
  // if every comma must be followed by a newline, then every element
  // in comps after the first one must begin with \n
  if (!comps.slice(1).every(s => s.startsWith('\n'))) {
    alert("every comma must be followed with a newline");
    return false;
  }
  return true;
}