我已经尝试过，但是我的程序似乎不起作用

Question

I have created a system to translate english into pig latin, but it doesn't work. The problem is that the variable fl isn't showing. Does anyone know how to fix this?

 function piglatinify() { var word = document.getElementById("textbox").value; var fl = word.substr(1, 1); var wordwithoutfl = word.substr(2, 999); var piglatinword = wordwithoutfl.concat(fl); var piglatinword = piglatinword.concat("ay"); document.write(piglatinword); } 

 <textarea id="textbox"></textarea><br> <button onclick="piglatinify()">See it in pig latin...</button> 

Answer 1

The length parameter of the substr() method is optional. Change this:

var wordwithoutfl = word.substr(2, 999);

to this:

var wordwithoutfl = word.substr(2);

Also, condense these lines:

var piglatinword = wordwithoutfl.concat(fl);
var piglatinword = piglatinword.concat("ay");

to this:

var piglatinword = wordwithoutfl + fl + "ay";

For two reasons: 1) This makes it so that you are not declaring the variable piglatinword twice, and 2) the "+" operator has better performance than the concat() method (see this page on the Mozilla Developer Network).

Answer 2

A short way to do it would be:

    function piglatinify() {
      var word = document.getElementById("textbox").value;
      var piglatinword = word.substr(1) + word.substr(0, 1) + "ay";
      document.write(piglatinword);
    }

Also, remember that Javascript starts counting at 0, so to get the first letter, you need to do substr(0, 1). substr(1, 1) will get you the second letter.

word.substr(2, 999) can be changed to word.substr(2), as the length parameter is optional, but that would get you the string, minus the first 2 letters (qwerty => erty). Therefore, you would need to make it word.substr(1).