I tried to use the event API, such as paste.
In my JavaScript code, it does not work.
when the user copy text from form,how can I get the selected value?
UPDATE
I use following code and it works.
function handlePaste(e) {
  var clipboardData, pastedData;
  // Stop data actually being pasted into div 
  e.stopPropagation();
  e.preventDefault();
  // Get pasted data via clipboard API 
  clipboardData = e.clipboardData || window.clipboardData;
  pastedData = clipboardData.getData('Text');
  // Do whatever with pasteddata 
  alert(pastedData);
}
document.getElementById('editableDiv').addEventListener('paste', handlePaste);
 
    