Window.prompt仅接受数值

Question

I am trying (unsuccessfully although) to make a window.prompt which will accept only numeric values (0,1,2,3,...) but I believe that something I am doing wrong. Look at my function. Am I missunderstanding something? how can i use this regex /^[0-9.,]+$/ in my code?

<script>
    function save3() {
      var pn = 4; 
      do{
        var selection = parseInt(window.prompt("Give the User Id:", "Type a number!"), 10);
if (selection != (/^[0-9.,]+$/)){
    window.alert("xana");       
    }
        }while(isNaN(selection));
    $("#user_id").val(selection)
      //$("#user_id").val(prompt("Give the User Id:"))
      do{
        var selection2 = parseInt(window.prompt("Give the Book Id:", "Type a number!"), 10);
        }while(isNaN(selection2));
    $("#book_id").val(selection2)
      //$("#book_id").val(prompt("Give the Book Id:"))
      do{
        var selection3 = parseInt(window.prompt("Give the Game Id:", "Type a number!"), 10);
        }while(isNaN(selection3));
    $("#game_id").val(selection3)
      //$("#game_id").val(prompt("Give the Game Id:"))
      $("#site_id").val(pn)
    }
  </script>

Answer 1

You can use RegExp.test() to check your input like:

const isInteger = /^(\d)+$/g;
if(isInteger.test(selection)) {
  console.log('Correct input!');
  // ... code
}

Answer 2

You should reduce your code to the minimum required to reproduce the issue, eg:

  var selection = parseInt(window.prompt("Give the User Id:", "Type a number!"), 10); if (selection != (/^[0-9.,]+$/)){ console.log('fail'); } else { console.log('pass'); } 

This returns "fail" for any value because you're testing a number against a regular expression object, which can never be equal.

If you want the user to only enter digits, period (.) and comma (,), then leave the entered text as a string and test it using the test method. I've also inverted the test so it makes more sense:

 var selection = parseInt(window.prompt("Give the User Id:", "Type a number!"), 10); if ( /^[0-9.,]+$/.test(selection)) { console.log('pass'); } else { console.log('fail'); }