Generating a random number in JavaScript and passing it to an HTML input tag - Stack Overflow

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My script, stored as a separate js file:

function randomNumber(len) {
    var randomNumber;
    var n = '';

    for(var count = 0; count < len; count++) {
        randomNumber = Math.floor(Math.random() * 10);
        n += randomNumber.toString();
    }

    return n;
}

var finalSequence = randomNumber(9);

document.write('<INPUT TYPE=TEXT NAME="ACCOUNT" VALUE='+finalSequence +' MAXLENGTH=16 SIZE=16>');

I have included this td tag in my html file:

<td align=left><FONT FACE="Arial,Helvetica"><script src="nexgen.js"></script>

Do you suggest that I write my script inside the html file itself?

I would like to display the generated random number using an input tag, such as that below. How do I do this?

<INPUT TYPE=TEXT NAME="ACCOUNT" VALUE= ???  MAXLENGTH=16 SIZE=16>

Update:

I am bining the JavaScript and html in one html file as follows. Please see if you can find any mistakes because the number generated is not being displayed on html page.

Javascript part:

function randomNumber(len) {
    var randomNumber;
    var n = '';

    for(var count = 0; count < len; count++) {
        randomNumber = Math.floor(Math.random() * 10);
        n += randomNumber.toString();
    }

    document.getElementById("ACCOUNT").value = n;
    return n;
}

HTML part:

<tr>
  <td><FONT FACE="Arial,Helvetica" color="red"> Transaction ID: </font></td>
  <td align=left>
    <FONT FACE="Arial,Helvetica">
      <script> randomNumber(9); </script>
      <INPUT TYPE=TEXT NAME="ACCOUNT" ID="ACCOUNT" VALUE="" MAXLENGTH=16 SIZE=16 readonly>
    </font>
  </td>
</tr>

My script, stored as a separate js file:

function randomNumber(len) {
    var randomNumber;
    var n = '';

    for(var count = 0; count < len; count++) {
        randomNumber = Math.floor(Math.random() * 10);
        n += randomNumber.toString();
    }

    return n;
}

var finalSequence = randomNumber(9);

document.write('<INPUT TYPE=TEXT NAME="ACCOUNT" VALUE='+finalSequence +' MAXLENGTH=16 SIZE=16>');

I have included this td tag in my html file:

<td align=left><FONT FACE="Arial,Helvetica"><script src="nexgen.js"></script>

Do you suggest that I write my script inside the html file itself?

I would like to display the generated random number using an input tag, such as that below. How do I do this?

<INPUT TYPE=TEXT NAME="ACCOUNT" VALUE= ???  MAXLENGTH=16 SIZE=16>

Update:

I am bining the JavaScript and html in one html file as follows. Please see if you can find any mistakes because the number generated is not being displayed on html page.

Javascript part:

function randomNumber(len) {
    var randomNumber;
    var n = '';

    for(var count = 0; count < len; count++) {
        randomNumber = Math.floor(Math.random() * 10);
        n += randomNumber.toString();
    }

    document.getElementById("ACCOUNT").value = n;
    return n;
}

HTML part:

<tr>
  <td><FONT FACE="Arial,Helvetica" color="red"> Transaction ID: </font></td>
  <td align=left>
    <FONT FACE="Arial,Helvetica">
      <script> randomNumber(9); </script>
      <INPUT TYPE=TEXT NAME="ACCOUNT" ID="ACCOUNT" VALUE="" MAXLENGTH=16 SIZE=16 readonly>
    </font>
  </td>
</tr>

• javascript
• html

Share Improve this question Follow edited Nov 21, 2016 at 23:34 Ninjakannon 3,81977 gold badges5555 silver badges8181 bronze badges asked Mar 11, 2014 at 2:34 user3329255user3329255 2311 gold badge11 silver badge44 bronze badges 1

• I am bining the javascript and html in one html file. as follows. please see if you can find any mistakes because the number generated is not being displayed on html page. – user3329255 Commented Mar 11, 2014 at 6:13

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6 Answers 6

Sorted by: Reset to default 4

Assign an ID to your input element, then in your JavaScript, assign the generated value to that element.

function randomNumber(len) {
  var randomNumber;
  var n = '';

  for (var count = 0; count < len; count++) {
    randomNumber = Math.floor(Math.random() * 10);
    n += randomNumber.toString();
  }
  return n;
}

document.getElementById("ACCOUNT").value = randomNumber(9);

<INPUT TYPE=TEXT NAME="ACCOUNT" ID="ACCOUNT" VALUE="" MAXLENGTH=16 SIZE=16>

Working jsFiddle.

BTW, if you want to generate a random number of a certain length, you can do it in much bigger chunks than one digit at a time, e.g.:

function longRandom(length) {
  var n = '';
  while (n.length < length) {
    n += ('' + Math.random()).split('.')[1];
  }
  return n.substr(0, length);
}

console.log(longRandom(42)); // 134434793311713322660940870849409308530315

will do it in chunks of about 15 digits on each loop. :-)

A random number is generated using javascript and also passed in the input form tag in html using code similar to ones mentioned below.

Javascript :

function randomNumber(len) {
    var randomNumber;
    var n = '';

    for(var count = 0; count < len; count++) {
        randomNumber = Math.floor(Math.random() * 10);
        n += randomNumber.toString();
    }
    return n;
}

window.onload = function() {
document.getElementById("ACCOUNT").value = randomNumber(9);
};

HTML part:

<INPUT TYPE=TEXT NAME="ACCOUNT" ID="ACCOUNT" VALUE=""  MAXLENGTH=16 SIZE=16>

Something like this, but you can do that in different ways:

http://jsbin./hujefopa/1/edit

function rand(len){
  return Math.floor(Math.random() * Math.pow(10, len));
}

function setRand(){
   document.getElementById('rand').value = rand(9); 
}

<!DOCTYPE html>
<html>
<head>
  <meta charset="utf-8">
  <title>JS Bin</title>
</head>
<body onload="setRand()">
  <input type="text" id="rand">
</body>
</html>

Please note that:

1. If your script is small, it's better to put it inside the page itself rather than importing a new file (new request to the server).
2. Using document.write is not remended. See this question.

3. To update the value of html input you can use:

   document.getElementById('id-of-your-input-element').value = newValue;
   

   or using jQuery:

   $('#id-of-your-input-element').val(newValue);
   

HTML PART

    <tr>
    <td><FONT FACE="Arial,Helvetica" color="red"> Transaction ID: </font></td>
    <td align=left>
    <FONT FACE="Arial,Helvetica">
    <INPUT TYPE=TEXT NAME="ACCOUNT" ID="ACCOUNT" VALUE="" MAXLENGTH=16 SIZE=16 
    readonly>
    </font>
    </td>
    </tr>

JavaScript Part

     <script>
    document.getElementById('ACCOUNT').value=Math.floor(Math.random() * 10);
    </script>

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