js验证上传文件类型，js操作本地文件

js的一些基本应用，时间久了容易忘记。先记这吧
 

 function lastname(){
		 //获取欲上传的文件路径
		var filepath = document.getElementById("img").value; 
		//为了避免转义反斜杠出问题，这里将对其进行转换
		var re = /(\\+)/g; 
		var filename=filepath.replace(re,"#");
		//对路径字符串进行剪切截取
		var one=filename.split("#");
		//获取数组中最后一个，即文件名
		var two=one[one.length-1];
		//再对文件名进行截取，以取得后缀名
		var three=two.split(".");
		 //获取截取的最后一个字符串，即为后缀名
		var last=three[three.length-1];
		//添加需要判断的后缀名类型
		var tp ="jpg,gif,bmp,JPG,GIF,BMP,png";
		//返回符合条件的后缀名在字符串中的位置
		var rs=tp.indexOf(last);
		//如果返回的结果大于或等于0，说明包含允许上传的文件类型
		if(rs!=-1){
		 return true;
		 }else{ 
		 alert("您选择的上传文件不是有效的图片文件！"); 
		 //$('#subbutton').attr("disabled", "disabled");
		 return false;
	  }
  }

js操作本地文件，这个需要更改浏览器的安全设置才能有效果的，前面的代码是对字符串进行的base64编码

function base64encode(str) {
    var out, i, len;
    var c1, c2, c3;
    len = str.length; 
    i = 0;
    out = "";
    while(i < len) {
	 c1 = str.charCodeAt(i++) & 0xff;
	 if(i == len)
	 {
	     out += base64EncodeChars.charAt(c1 >> 2);
	     out += base64EncodeChars.charAt((c1 & 0x3) << 4);
	     out += "==";
	     break;
	 }
	 c2 = str.charCodeAt(i++);
	 if(i == len)
	 {
	     out += base64EncodeChars.charAt(c1 >> 2);
	     out += base64EncodeChars.charAt(((c1 & 0x3)<< 4) | ((c2 & 0xF0) >> 4));
	     out += base64EncodeChars.charAt((c2 & 0xF) << 2);
	     out += "=";
	     break;
	 } 
	 c3 = str.charCodeAt(i++);
	 out += base64EncodeChars.charAt(c1 >> 2);
	 out += base64EncodeChars.charAt(((c1 & 0x3)<< 4) | ((c2 & 0xF0) >> 4));
	 out += base64EncodeChars.charAt(((c2 & 0xF) << 2) | ((c3 & 0xC0) >>6));
	 out += base64EncodeChars.charAt(c3 & 0x3F);
 }
    return out;
}

function getInfo(){
	var declin=';'; 
	var imei;
	var curr_staff_num;
	var update_staff_num;
	var password;
	var ip;  
	var port;  
	var resendTime;
	var dowmloadPage;
	var commandPage;
	var dataTransportPage;  

	imei = document.forms[0].imei.value;   
	curr_staff_num ='<bean:write name="te" property="terminal_no" scope="request"/>';    
	update_staff_num = document.forms[0].terminal_no.value;  
	password =  '<bean:write name="constant" property="constant_password" scope="request"/>';
	ip = '<bean:write name="constant" property="constant_ip" scope="request"/>';
	port = '<bean:write name="constant" property="constant_port" scope="request"/>';  
	resendTime = '<bean:write name="constant" property="constant_connection_time" scope="request"/>';
	dowmloadPage = '<bean:write name="constant" property="constant_down_address" scope="request"/>';
	commandPage = '<bean:write name="constant" property="constant_command_address" scope="request"/>';
	dataTransportPage = '<bean:write name="constant" property="constant_location_address" scope="request"/>';
	
	var str = imei+declin+curr_staff_num+declin+update_staff_num+ 
				declin+password+declin+ip+declin+port
				+declin+resendTime+declin+dowmloadPage+
				declin+commandPage+declin+dataTransportPage+declin;
	return str; 
	//alert(str);  
} 
//保存至移动设备
function saveToTermianl(){  
		var str = getInfo(); 
		//alert(str); 
		var dealStr = base64encode(str);
		//alert(dealStr); 
                 //操作本地文件的对象
		var fso = new ActiveXObject("Scripting.FileSystemObject");  
		 
		var drives = "c,d,e,f,g,h,i,j,k,l,m,n,o,p,q,r"; //,s,t,u,v,w,x,y,z";
		var array = drives.split(","); 
		 
		for(var i =0 ;i<array.length;i++){ 
			var filepath = array[i]+":\\QinYiApp\\Settting\\profile.bin";  
			alert(filepath);     
			if (fso.FileExists(filepath)){      
			   	 //alert("fold exists");     
			    var f1 = fso.CreateTextFile(array[i]+":\\QinYiApp\\Settting\\SettingInfo.txt", true);
			    f1.WriteLine(dealStr);       
			    f1.close(); 
			    alert('文件已成功写入终端，请断开终端与电脑连接并重启终端！');
			    document.forms[0].submit(); 
			    return;
			 } 
		}  
		alert('修改设置失败！没发现终端设备请将终端连接好电脑，并选择存储模式！');
		window.close();
}