<html> <head> <meta http-equiv="content-type" content="text/html; charset=iso-8859-1" /> <meta name="author" content="" /> <script type="text/javascript"> function run(){ var cb = document.getElementById("cb"); if(document.getElementById("cekbox").checked == true){ cb.disabled = true; }else{ cb.disabled = false; } } </script> <title>Enable/Disable ComboBox</title> </head> <body> <input type="checkbox" name="a" id="cekbox" onclick="run();" />Disable Checkbox<br /><br /> <select id="cb" size="1"> <option>a</option> <option>b</option> </select> </body> </html>