title: Detect Double byte characters
body: <p>I have to write a JavaScript function that will validate if the entered text is in Double Byte.The text box should accept only double byte Japanese characters, double byte English characters and double byte special characters. I tried using a number of solutions offered in other blogs but the validation fired either for single byte English or single byte Japanese characters i.e validation fired fine for single byte English characters and failed for single byte Japanese.</p>