function check(){
	if(!trim(form.ID.value)){alert('The ID is required.');form.ID.focus();return false;}
	if(!ischar(form.ID.value)){form.ID.select();return false;}
	if(!checkBytes(form.ID.value)){form.ID.select();return false;}
	if(trim(form.ID.value).length < 4){alert('Invalid ID.');form.ID.focus();return false;}
	if(!trim(form.PW.value)){alert('The password is required.');form.PW.focus();return false;}
	if(!ischar(form.PW.value)){form.PW.select();return false;}
	if(!checkBytes(form.PW.value)){form.PW.select();return false;}
	if(trim(form.PW.value).length < 4){alert('Invalid password.');form.PW.focus();return false;}
        form.submit();
}
function trim(instr){
        return instr.replace(/^[\s]*/gi,'').replace(/[\s]*$/gi,'');
}
function ischar(s){
        var errorChar;
        var badChar = "><[]{}?/\+=|'~!#$%^&()`"; 

        errorChar = isCharsInBagEx(s,badChar);
        if (errorChar != ''){
                alert('Invalid ID or password. ('+ badChar +')');
                return false;
        }
        return true;
}
function isCharsInBagEx(s,bag){ 
        var i,c;
        for (i = 0; i < s.length; i++){ 
                c = s.charAt(i);
                if (bag.indexOf(c) > -1){
                return c
                }
        }
        return '';
}
function checkBytes(obj) { 
   	var hasChinese = false;
   	var n = obj.length;
  	for(var i=0;i<n;i++){
    		var str = encodeURI(obj.charAt(i));
       		if(str.length == 9){
        		hasChinese = true;
        		break;
        	}
   	}
   	if(hasChinese){
   		alert("Invalid ID or password.");
   		return false;
   		return true;
   	}else{
   		return true;
   	}
}
function isNumeric(Key){
       if((Key < 48 || Key > 57)){
               window.event.keyCode = 0;
       } 
}
function checkKey(key){
        if((key < 48 || key > 57) && (key < 65 || key > 90) && (key < 97 || key > 122) && (key != 95)){
                window.event.keyCode = 0;
        } 
}