CODEWITHSUNDEEP
javascripthtml
Harold Sota
Harold Sota

Reputation: 7566

How to check if a html control exists?

How do I check if an HTML control exists?

This is my code:

var id = ...
if(document.getElementById(id)!=null)
{
   //do something
}

if the html control is radio doesn't work.

How is this done?

Upvotes: 2

Views: 22817

Answers (2)

Frode
Frode

Reputation: 540

function validate(ValFrm) {
  var len = ValFrm.elements.length;

  for (i = 0; i < len; i++) {

    if (ValFrm.elements[i].required == "Yes") {
      if (ValFrm.elements[i].value == "") {
        alert('The ' + ValFrm.elements[i].title + ' is required to contain data.');
        ValFrm.elements[i].focus();
        return false;
      }
    }

    if (ValFrm.elements[i].type == "radio") {
      if (!ValFrm.app[0].checked && !ValFrm.app[1].checked) {
        alert('Please accept or deny.');
        return false;
      }
    }

  }
}

Upvotes: 1

Daniel Vassallo
Daniel Vassallo

Reputation: 344291

Further to your comments above, you should use a unique id for each radio button, but you can use the same name for your radio group. Consider the following example:

<!DOCTYPE html>
<html> 
<head> 
   <meta http-equiv="content-type" content="text/html; charset=UTF-8"/> 
   <title>Testing document.getElementById()</title> 
</head> 
<body> 
   <input type="radio" id="my_radio_1_id" name="my_radios"> My Radio Button 1
   <input type="radio" id="my_radio_2_id" name="my_radios"> My Radio Button 2

   <script type="text/javascript"> 
     if (document.getElementById('my_radio_1_id')) {
       alert('It Exists');
     }
   </script> 
</body> 
</html>

It will alert 'It Exists' as expected.

Upvotes: 9

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