Exception handling in JavaScript

Exception handling in JavaScript

Source:- Exception handling in JavaScript

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Exception Handling

In programming, exception handling is a process or method used for handling the abnormal statements in the code and executing them. It also enables to handle the flow control of the code/program. For handling the code, various handlers are used that process the exception and execute the code. For example, the Division of a non-zero value with zero will result into infinity always, and it is an exception. Thus, with the help of exception handling, it can be executed and handled.

There are following statements that handle if any exception occurs: — -

-> throw statements

-> try…catch statements

-> try…catch…finally statements.

Code example to place a number between 5 and 10 inside inputbox

HTML:-

<p>Please input a number between 5 and 10:</p>
<input id="demo" type="text">
<button type="button" onclick="myFunction()">Test Input</button>
<p id="p01"></p>

JS:-

function myFunction() {
  var message, x;
  message = document.getElementById("p01");
  message.innerHTML = "";
  x = document.getElementById("demo").value;
  try { 
    if(x == "")  throw "is empty";
    if(isNaN(x)) throw "is not a number";
    x = Number(x);
    if(x > 10)   throw "is too high";
    if(x < 5)  throw "is too low";
  }
  catch(err) {
    message.innerHTML = "Input " + err;
  }
  finally {
    document.getElementById("demo").value = "";
  }
}