value of textbox has changed or not

how to find whether a value of textbox has changed or not using javascript(even if we copy something and paste it using 开发者_运维问答right click and paste)

---

Try using the textbox onchange event

---

use the keyup and click event listeners

---

Go about something like this:

var elem = document.getElementById('id here');

elem.onchange = function(){
  // your code here......
};

More Info:

http://www.w3schools.com/js/js_events.asp

---

if you need to check this on separate event and can't use onchange event, you can compare objects defaultValue and value

---

You can use the onchange event to track if the contents have been changed. It is also possible to compare current input[type=text].value to input[type=text].defaultValue. defaultValue will have the original value supplied in the value-attribute.