generate random number on page load and store in a hidden form field

Question

I need to generate a random number on every web page load and store that number in a hidden form field (id="field10"). Following is my code but its wrong. Quick help is highly appreciated.

<script type='text/javascript'>
  function test(final){
var min = 1;
var max = 9999999999;
var num = Math.floor(Math.random() * (max - min + 1)) + min;
var timeNow = new Date().getTime(); 
var final = num+'_'+timeNow;
document.getElementById('field10').value=test(final);
  }
window.onload = test;
</script>

Answer 1

Lot of issues. Will give a quicker solution:

function test() {
  var min = 1;
  var max = 9999999999;
  var num = Math.floor(Math.random() * (max - min + 1)) + min;
  var timeNow = new Date().getTime();
  document.getElementById('field10').value = num + '_' + timeNow;
}
window.onload = test;

I just removed few lines, which are unnecessary. This will work well. A glimpse of what I have done:

• Removed all the parameters.
• Removed the final variable (might cause troubles sometimes).
• Directly set the value to the element.
• Beautified the code.

Snippet

 function test() { var min = 1; var max = 9999999999; var num = Math.floor(Math.random() * (max - min + 1)) + min; var timeNow = new Date().getTime(); document.getElementById('field10').value = num + '_' + timeNow; } window.onload = test; setTimeout(function () { console.log(document.getElementById('field10').value); }, 500); 

 <input type="hidden" id="field10" /> 

Answer 2

As a best practice, always put your scripts just before your closing body tag. You will not need to do the window.onload thing if you follow this as the DOM will already be loaded by then. Though window.onload might be necessary in some cases.

 function randomNumber() { var min = 1; var max = 9999999999; return Math.floor(Math.random() * (max - min + 1)) + min; } document.getElementById('field10').value = randomNumber() + new Date().getTime(); 

 <!-- add type="hidden", i omitted here so you can see the results --> <input id="field10">