post hoc ergo propter hoc

Just now I was trying to restrict the backslash input in textbox in flash. Many I have tried, none successful. Good that I came across this post eventually, and it helps a LOT.

The original documentation in flash is stated as such :
"You can use a backslash to enter a ^ or – verbatim. The accepted backslash sequences are \-, \^ or \\. The
backslash must be an actual character in the string, so when specified in ActionScript, a double backslash must be used. "

That is so…..unclear……

Therefore when u try to restrict the "\", u end up have to use "^\\\\".
e.g. input_txt.restrict = "^\\\\"

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Sometimes when you need to save the data from flash to XML, certain special characters should be taken care of. In XML, ‘<’, ‘>’, ‘/’ and ‘"’ all has its special/reserved meaning. The way I did is to convert those characters to a even more "special" character, that hopefully user wont type out from keyboard.

public static function encodeSpecialChars(str:String):String {
   var len:Number = str.length;

   for(var i:Number=0; i<len; i++) {
      switch (str.charAt(i)) {
         case "<":
            str = str.slice(0, i) + String.fromCharCode(170) + str.slice(i+1, len);
            break;
         case ">":
            str = str.slice(0, i) + String.fromCharCode(176) + str.slice(i+1, len);
            break;
         case "/":
            str = str.slice(0, i) + String.fromCharCode(178) + str.slice(i+1, len);
            break;
         case "\"":
            str = str.slice(0, i) + String.fromCharCode(179) + str.slice(i+1, len);
            break;
         case "\"":
            str = str.slice(0, i) + String.fromCharCode(164) + str.slice(i+1, len);
            break;

         default:
            break;
      }
   }

   return str;
}

public static function decodeSpecialChars(str:String):String {
   var len:Number = str.length;

   for(var i:Number=0; i<len; i++) {
      switch (str.charAt(i)) {
         case String.fromCharCode(170):
            str = str.slice(0, i) + "<" + str.slice(i+1, len);
            break;
         case String.fromCharCode(176):
            str = str.slice(0, i) + ">" + str.slice(i+1, len);
            break;
         case String.fromCharCode(178):
            str = str.slice(0, i) + "/" + str.slice(i+1, len);
            break;
         case String.fromCharCode(179):
            str = str.slice(0, i) + "\"" + str.slice(i+1, len);
            break;
         case String.fromCharCode(164):
            str = str.slice(0, i) + "\"" + str.slice(i+1, len);
            break;

         default:
            break;
      }
   }

   return str;
}

written by admin \\ tags: actionscript, restrict