IPアドレス、サブネットマスク、gateway_javascriptのjs論理判定スキル

function checkIP(ip) 
{ 
 obj=ip;
 var exp=/^(\d{1,2}|1\d\d|2[0-4]\d|25[0-5])\.(\d{1,2}|1\d\d|2[0-4]\d|25[0-5])\.(\d{1,2}|1\d\d|2[0-4]\d|25[0-5])\.(\d{1,2}|1\d\d|2[0-4]\d|25[0-5])$/; 
 var reg = obj.match(exp); 
 if(reg==null) 
 { 
  return false;//不合法
 } 
 else 
 { 
  return true; //合法
 } 
}
 
function checkMask(mask) 
{ 
 obj=mask; 
 var exp=/^(254|252|248|240|224|192|128|0)\.0\.0\.0|255\.(254|252|248|240|224|192|128|0)\.0\.0|255\.255\.(254|252|248|240|224|192|128|0)\.0|255\.255\.255\.(254|252|248|240|224|192|128|0)$/; 
 var reg = obj.match(exp); 
 if(reg==null) 
 { 
   return false; //"非法"
 } 
  else 
 { 
   return true; //"合法"
 } 
} 
 var static_ip= document.getElementById('static_ip').value;
  var static_mask= document.getElementById('static_mask').value; 
  var static_gw= document.getElementById('static_gw').value;

  
  if (static_ip=='')
  {
   // $("#static_ip_error").css("display","block");
   document.getElementById('static_ip').focus();
   return false;
  }else if(!checkIP(static_ip))
  {
   //$("#static_ip_error").css("display","none");
   document.getElementById('static_ip').focus();
   return false;    
  }
   
  if(static_mask=='')
  { 
   //$("#static_mask_error").css("display","block");
   document.getElementById('static_mask').focus();
   return false;  
  }else if(!checkMask(static_mask))
  {
   //$("#static_mask_error").css("display","none"); 
   document.getElementById('static_mask').focus();
   return false;  
  }  
  
  if(static_gw=='')
  { 
   //$("#static_gw_error").css("display","block");
   document.getElementById('static_gw').focus();
   return false;  
  }else if(!checkIP(static_gw))
  {
   //$("#static_gw_error").css("display","none");
   document.getElementById('static_gw').focus();
   return false;    
  } 
 

 if(static_ip == static_mask || static_mask == static_gw || static_mask == static_gw)
 {
  alert('地址输入错误！');
  return false; //3个地址不能相同
 }
 
 var static_ip_arr = new Array;
 var static_mask_arr = new Array;
 var static_gw_arr = new Array;
  
 static_ip_arr = static_ip.split(".");
 static_mask_arr = static_mask.split(".");
 static_gw_arr = static_gw.split(".");

 var res0 = parseInt(lan_ip_arr[0]) & parseInt(static_mask_arr[0]);
 var res1 = parseInt(lan_ip_arr[1]) & parseInt(static_mask_arr[1]);
 var res2 = parseInt(lan_ip_arr[2]) & parseInt(static_mask_arr[2]);
 var res3 = parseInt(lan_ip_arr[3]) & parseInt(static_mask_arr[3]);
 
 var res0_gw = parseInt(static_gw_arr[0]) & parseInt(static_mask_arr[0]);
 var res1_gw = parseInt(static_gw_arr[1]) & parseInt(static_mask_arr[1]);
 var res2_gw = parseInt(static_gw_arr[2]) & parseInt(static_mask_arr[2]);
 var res3_gw = parseInt(static_gw_arr[3]) & parseInt(static_mask_arr[3]);
 
 if(res0==res0_gw && res1==res1_gw && res2==res2_gw && res3==res3_gw)
 {
  
 }else{
  alert('IP地址与子网掩码、网关地址不匹配！');
  return false;
 }

function checkIP(ip) 
{ 
  obj=ip;
  var exp=/^(\d{1,2}|1\d\d|2[0-4]\d|25[0-5])\.(\d{1,2}|1\d\d|2[0-4]\d|25[0-5])\.(\d{1,2}|1\d\d|2[0-4]\d|25[0-5])\.(\d{1,2}|1\d\d|2[0-4]\d|25[0-5])$/; 
  var reg = obj.match(exp); 
  if(reg==null) 
  { 
    return false;//不合法
  } 
  else 
  { 
    return true; //合法
  } 
}
 
function checkMask(mask) 
{ 
  obj=mask; 
  var exp=/^(254|252|248|240|224|192|128|0)\.0\.0\.0|255\.(254|252|248|240|224|192|128|0)\.0\.0|255\.255\.(254|252|248|240|224|192|128|0)\.0|255\.255\.255\.(254|252|248|240|224|192|128|0)$/; 
  var reg = obj.match(exp); 
  if(reg==null) 
  { 
     return false; //"非法"
  } 
   else 
  { 
     return true; //"合法"
  } 
}