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COMPUTER SOFTWARE APPLICATION - CITS
Syntax
try {
Block of code to try
}
catch(err) {
Block of code to handle errors
}
finally {
Block of code to be executed regardless of the try / catch result
}
Example
function myFunction() {
const message = document.getElementById(“p01”);
message.innerHTML = “”;
let x = document.getElementById(“demo”).value;
try {
if(x.trim() == “”) 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 = “Error: “ + err + “.”;
}
finally {
document.getElementById(“demo”).value = “”;
}
}
The Error Object
JavaScript has a built in error object that provides error information when an error occurs.
The error object provides two useful properties: name and message.
Error Object Properties
Property Description
name Sets or returns an error name
message Sets or returns an error message (a string)
Error Name Values
Six different values can be returned by the error name property:
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CITS : IT&ITES - Computer Software Application - Lesson 37 - 46
