js method to monitor text box status in real time_javascript skills

<script> <br>//Function executed when the status changes<br>function handle( ) <br>{ <br>document.getElementById('msg').innerHTML = document.getElementById('txt').value; <br>} <br><br>//if("v"==" v") only returns true under IE, including IE8 <br>//if(/msie/i.test(navigator.userAgent)) can also effectively determine <br>if("v"=="v" ){ <br>//IE monitors the text box and assigns a function. There cannot be brackets after the function name <br>document.getElementById('txt').onpropertychange = handle; <br>}else{ <br>//Google The browser uses the add event function to add events to the text box and assign the method to be executed. Similarly, brackets cannot be added after the method name <br>document.getElementById('txt').addEventListener("input", handle); <br> } <br></script>