The value of returnValue in the unload event cannot be obtained by the parent window

wytcloud

In the opened window
window.unload ()
{
  returnValue = "true";
}

In parent window
var ret = window.showModalDialog ();
alert (ret);
The ret value is not "true", but is undefined.

hen_ab

It should not be such a process, it should be:
Assign value to returnValue in the onload of the window, and then assign the value to the corresponding button or elsewhere. For example, it is equal to false when onload, and true otherwise, so that the return value is guaranteed to be flase when the user has no choice.

shenmue024

returnValue =>
window.returnValue