Parent window window.showModalDialog Window.returnvalue return value of child window

The parent window opens the child window page:

var Fatherwindow = document.all.dealreason;//Want to pass the value
Win = window.showModalDialog (strURL, Fatherwindow, "dialogwidth=800px;dialogheight=600px;");

strURL is the child window page, Fatherwindow is the value to pass, win is the value returned by the child window
Document.all.dealReason.value = win;

child window:

var dialogargument = window.dialogarguments.value;//takes the value of the parent window

Window.returnvalue = dialogargument;//value to parent window

Window.close ();