有人请解释这个JavaScript

Question

http://codepen.io/anon/pen/JdRJGz

I've tried for a while and it seems that the script is simply not running. I'm sure that I have js enabled , maybe there's a bug i didn't catch?

function hello(){
``getElementById("message").style.display="block";
  getElementById("block").style.display="block";
};

function disappear(){
  getElementById("message").style.display="none";
  getElementById("block").style.display="none";
};

Answer 1

If you would open up the developer console, you'd see the problem immediately: getElementById() is not defined. You're looking for

  document.getElementById("message").style.display = "block";

Answer 2

getElementById is a member of the Document object

Correct your code like

function hello(){
    document.getElementById("message").style.display="block";
    document.getElementById("block").style.display="block";
};

function disappear(){
    document.getElementById("message").style.display="none";
    document.getElementById("block").style.display="none";
};

http://codepen.io/anon/pen/OVRgmW

Answer 3

here let me explain,this hello and disappear r two functions which will trigger when u do an event like button click or something in ur code, message is an id of an element u set in ur page, n ur calling it specifically using its id and ur setting its style. I dont knw how u want ur code to behave but with the given information this is the best assumption i can make.