I have a print button with `id="print_req"`. I wrote some Javascript code for printing a page, which is triggered by clicking on this button, and I also want to hide this button before printing, and show it after whole printing process.i mean not to print button in my printed document. Here is my code:

```
$(document).ready(function(){
    $("#print_req").click(function(){
        $("#print_req").css("display","none");
        window.print();  
    });

    $("#print_req").css("display","block");
    return false;   
});

```

This correctly hide that button, but when the printing process get done, the button won't show again! What is the problem?