document.getElementById() doesn't work?
html, javascript
Solution
Put your script AFTER the actual element, otherwise by the time your javascript code runs, there's not yet such element in the DOM.
<html>
<body>
<input type="button" id="btn1" value="Clickme" onclick="alert('1')" />
<script>
var x = document.getElementById('btn1');
alert(x);
</script>
</body>
</html>
Alternatively put your script in a DOM ready event to ensure that the DOM is fully loaded by the browser before attempting to manipulate it:
<html>
<body>
<script>
window.onload = function() {
var x = document.getElementById('btn1');
alert(x);
};
</script>
<input type="button" id="btn1" value="Clickme" onclick="alert('1')" />
</body>
</html>
Problem
No much to say, ``` <html> <body> <script> var x = document.getElementById('btn1'); alert(x); </script> <input type="button" id="btn1" value="Clickme" onclick="alert('1')" /> </body> </html> ``` The alert message is `null` instead of a message contain details of the object or something like that. What is the problem?