hoe kan ik een .zip bestand downloaden via ajax request

<a href="#download" class="cb_down" title="Download">Download</a>

//  AJAX for Checkbox download		
$(document).on('click' , '.cb_down' , function() { 	
	
          var checkboxes_down = []; 
						
           $('.rafcheckbox').each(function() {   
		if(this.checked) {				
                checkboxes_down.push($(this).val()); 				     	
           }  
        });  
        checkboxes_down = checkboxes_down.toString(); 
		   		   
        $.ajax({  
                url:"", 								
                method:"POST",  
				
                data:{ checkboxes_down:checkboxes_down },  
                success:function(response){ 
														
			// geen response nodig
										
                } 
			
        });  
});

// Multiple download (checkboxes)
if(isset($_POST["checkboxes_down"])) { 

	// create a tmp folder for the zip file
	$tmpfolder = $MainFolderName.'/tmp';
	if (!is_dir($tmpfolder)) {
		 mkdir($tmpfolder, 0755, true);
	}

	$checkboxfiles = explode("," , $_POST["checkboxes_down"]); 
        $filename = "archive.zip";
	$filepath = $tmpfolder."/";
			
    foreach($checkboxfiles as $checkboxfile) {	
			
	Zip($checkboxfile, $tmpfolder."/archive.zip");	// "Zip" is functie die archive.zip file maakt						
	}

        if(file_exists($tmpfolder.'/archive.zip')){
						
								
		// http headers for zip downloads
		header("Pragma: public");
		header("Expires: 0");
		header("Cache-Control: must-revalidate, post-check=0, pre-check=0");
		header("Cache-Control: public");
		header("Content-Description: File Transfer");
		header("Content-type: application/octet-stream");
			
		header("Content-Disposition: attachment; filename=\"".$filename."\"");
		header("Content-Transfer-Encoding: binary");
		header("Content-Length: ". filesize($filepath.$filename));
						
		while (ob_get_level()) {
			ob_end_clean();
		}
		readfile($filepath.$filename);
		unlink($tmpfolder.'/archive.zip'); // unlink archive.zip			
		rmdir($tmpfolder); // remove tmpdir

		exit;
		
	}
}