```html <select name="test" id="test" onchange='checkEnvironment(this.value);'> <option value="1" selected>1</option> <option value="2">2</option> <option value="3">3</option> <option value="other">Other</option> </select> <div id="test_text_input" style="display: none; margin: 10px 0 0 25%;"> <input type="text" name="test_custom" id="test_custom" /> </div> ``` ```javascript <script type="text/javascript"> function checkEnvironment(val) { var element=document.getElementById('test_text_input'); if(val=='other') { element.style.display='block'; } else { element.style.display='none'; } } </script> ```
