Checker

In simple terms, the "check()" function helps us find things on a web page, move around when we type, do some calculations, and maybe show us some results later. It's like a little helper that does all these tasks for us! It retrieves table and input field elements by their IDs, and checks for specific key codes.

script.js

function check(){
    var tbl1=document.getElementById("tbl1");
    var tbl2=document.getElementById("tbl2");
    var ip1=document.getElementById("ip1");
    var ip2=document.getElementById("ip2");
    if(event.keyCode==9 || event.keyCode==16)
        return false;
    var ip = event.target || event.srcElement;
    if(ip.value){
        if(ip.value.length>=2 && ip.value!="10"){
            if(ip==ip1){
                $(ip2).focus();
            }
            else if(ip==ip2){
                $(ip).blur();
                location.replace("#result");
            }
        }
    }
    var w=[];
    if(ip1.value){
        w[0]=calculate(tbl1,ip1);
    }
    if(ip2.value){
        w[1]=calculate(tbl2,ip2);
    }
    cycle(w[0],w[1]);
    
}

Let's break it down step by step:

1. The function starts by looking for some important things on the page. It wants to find two tables, one called "tbl1" and another called "tbl2". It also wants to find two input fields, one called "ip1" and another called "ip2". It uses special commands like "document.getElementById()" to find these things.

2. Then, it checks if a certain key on the keyboard is pressed. The keys are like the buttons you press to type letters or numbers. The function wants to know if the key with the number 9 or the key with the number 16 is pressed. If it is, it will stop doing anything else and just go back to what it was doing before.

3. Next, it tries to figure out which input field is being used. It does this by looking at the place where you're typing, like the input field you clicked on. It looks at the "event" happening at that moment. An event is like a little message that tells the function what is happening. It tries to find the input field you're typing in by using "event.target" or "event.srcElement".

4. If you're typing something in the input field, the function checks how long the thing you typed is and if it's not equal to "10". If it has at least 2 characters and it's not exactly "10", something interesting happens!

5. It checks which input field you're typing in. If it's the first one, it does something called "focusing" on the second input field. It's like telling the computer to move the cursor to the second input field, so you can start typing there. If it's the second input field, it does something else. It stops you from typing more and takes you to a different part of the web page called #result.

6. After that, the function checks if there's anything typed in the first input field. If there is, it uses another special function called calculate() to do some calculations using the first table and the first input field.

7. Then, it checks if there's anything typed in the second input field. If there is, it uses the same calculate() function to do some calculations using the second table and the second input field.

8. Finally, it does something called cycle() and gives it the results of the calculations it did before. This cycle() function probably does something really important with those results, which we'll see in another section.

We have successfully understood the Checker function! Let's move on and understand the Average function of the Fill My Cycle.