//印刷css切替
function txtPrint( file ){
	var link = document.createElement('link');  
	with( link ) {  
		href = file;  
		type = 'text/css';  
		rel = 'stylesheet';  
		media = 'print';  
	}  
	
	var head = document.getElementsByTagName('head');  
	head.item(0).appendChild(link); 

	window.print();
	
}