Please gurus in the house, I am stuck and I need your help with JavaScript.

I am trying to apply JavaScript to a page on PC, but whenever I call a function, only the first function works. The other ones don't work. I have to remove other functions before a particular function will work.

Even when I am using only one function, and I call the same function a second time to use it on another element, it doesn't work.

What am I doing wrong?

Parts of the code posted below:


var monthsY = ["Jan", "Feb", "Mar", "Apr", "May", "June", "Jul", "Aug", "Sept", "Oct", "Nov", "Dec"];

function greeT(){
switch(new Date().getHours()){
case 0:
case 1:
case 2:
case 3:
case 4:
case 5:
case 6:
case 7:
case 8:
case 9:
case 10:
case 11:
greet = "Good morning";
break;

case 12:
case 13:
case 14:
case 15:
case 16:
greet = "Good afternoon";
break;

case 17:
case 18:
case 19:
case 20:
case 21:
case 22:
case 23:
greet = "Good evening"
break;
}
return greet;
}


function salut(y){
document.getElementById(y).innerHTML=greeT();
}

salut("salut";


var mo = function(x){
s=document.getElementById(x);
s.style.backgroundColor="green";
s.style.color="black";
s.style.fontSize="35px";
}

mo("mo";

Try adding comments to your codes so another can know what you are trying to do.

mbatuku2:
Try adding comments to your codes so another can know what you are trying to do.

Thanks for the reply.

Note that I have two functions I'm trying to use,
salut() and mo().

If I call the functions in this order:
salut()
mo()

salut() will work while mo() will not work.

If change the order like this:
mo()
salut()

Then mo() will work while salut() will not work.
All other code I add to the JavaScript does not work except the first one.

that's my problem.

donlyone:


Thanks for the reply.

Note that I have two functions I'm trying to use,
salut() and mo().

If I call the functions in this order:
salut()
mo()

salut() will work while mo() will not work.

If change the order like this:
mo()
salut()

Then mo() will work while salut() will not work.
All other code I add to the JavaScript does not work except the first one.

that's my problem.

Trying using your browser console to track the error.

hollyfat:


Trying using your browser console to track the error.

After applying all the tips I got online, I still keep getting this error on browser console :

Uncaught TypeError: cannot set property 'innerHTML' of null

donlyone:


After applying all the tips I got online, I still keep getting this error on browser console :

Uncaught TypeError: cannot set property 'innerHTML' of null

This might be due to the fact that you are trying to change the content of an element that does not exist

It will be clearer if you pasted the html code also.

BTW, you should replace the switch statement in the salute function with something like this:

  var hour =  new Date().getHours();
  if (hour <= 11) {
    greet = "Good morning";
  } else if (hour <= 16) {
    greet = "Good afternoon";
  } else {
    greet = "Good evening";
  }

DEVELOPING AN ANDROID APP, WHAT YOU SHOULD KNOW. http://techzone.com.ng/2016/05/05/developing- android-app-know/

Hi,
The problem in your code is in the way you have created the functions.

In JavaScript, there are two methods to create functions.
In the first method, the function is saved in a variable

For example,

var methodName = function(){
}
Using this method, you have to define the function before calling it.

This will work

var greet = function(){
//print greeting
}
greet()//method call after method definition

This won't work

greet() //method call before method definition
var greet= function(){
//print greeting
}

Method 2 is easier. You define the function like this

function greet(){
}

This way, no matter where you place your method call, the function will run.


It's safer to define your functions using the 2nd method. Make the change to the mo function in your code.
I hope this explanation is clear enough.

Thank you guys.

I really appreciate this.