In this tutorial, we will learn how to catch syntax errors in JavaScript. In JavaScript, we get will errors if we write any mistakes in code. Like, ReferenceError, i.e., when we call a variable that does not exist in our code. TypeError i.e. when we tried to change the value which is immutable or try to use a variable in an appropriate way. SyntaxError i.e. when we tried to interpret invalid code. We will learn more about this error in detail below. What is Syntax Error? A syntax error is thrown when there is a glitch in ... Read More

To catch all JavaScript errors, we can use the window.onerror() method which acts like a global try-catch statement. The onerror event handler was the first feature to facilitate error handling in JavaScript. The error event is fired on the window object whenever an exception occurs on the page. The onerror event handler provides three pieces of information to identify the exact nature of the error − Error message − The same message that the browser would display for the given error URL − The file in which the error occurred Line number− The line number in the given ... Read More

This tutorial teaches us how to remove the text part between two parts of a string with JavaScript, basically, we are given two ends that can be a string or a character and we have to remove the string lying in between them. In this tutorial, we are going to use the regular expression or JavaScript Regex to remove the text between two characters. We are going to use the replace() function of JavaScript. Syntax Let’s see the syntax of removing part of a string in between two characters or sub-strings of a given string using JavaScript Regex − var ... Read More

To remove all special characters from a JavaScript string, you can try to run the following code −Example                    var str = "@!Welcome to our website$$";          document.write(str);                    // Removing Special Characters          document.write(""+str.replace(/[^\w\s]/gi, ''));                      

To find multiple matches, write a JavaScript regular expression. You can try to run the following code to implement regular expression for multiple matches −Example                    var url = 'https://www.example.com/new.html?ui=7&demo=one&demo=two&demo=three four',          a = document.createElement('a');          a.href = url;          var demoRegex = /(?:^|[&;])demo=([^&;]+)/g,          matches,          demo = [];          while (matches = demoRegex.exec(a.search)) {             demo.push(decodeURIComponent(matches[1]));          }          document.write(demo);                  

To remove spaces in JavaScript, you can try to run the following regular expression. It removes the spaces from a string −Example Live Demo                    var str = "Welcome to Tutorialspoint";          document.write(str);                    //Removing Spaces          document.write(""+str.replace(/\s/g, ''));                       Output

In this tutorial, we will explore how we can replace a particular sub string in a string by using regular expressions in JavaScript. Sometimes we may want to replace a recurrent sub string in a string with something else. In such cases, regular expressions can be beneficial. Before using them to solve our current problem, let us see what regular expressions exactly are. Regular expressions are basically a pattern of characters that can be used to search different occurrences of that pattern in a string. Regular expressions make it possible to search for a particular pattern in a stream of ... Read More

JavaScript uses try…catch…finally to handle exceptions. The latest versions of JavaScript added exception-handling capabilities. JavaScript implements the try...catch...finally construct as well as the throw operator to handle exceptions.You can catch programmer-generated and runtime exceptions, but you cannot catch JavaScript syntax errors.SyntaxHere is the try...catch...finally block syntax −     ExampleYou can try to run the following code to learn how exceptions are handled in JavaScript −                                         Click the following to see the result:                          

In JavaScript, the functions wrapped with parenthesis are called “Immediately Invoked Function Expressions" or "Self Executing Functions.The purpose of wrapping is to the namespace and control the visibility of member functions. It wraps the code inside a function scope and decreases clashing with other libraries. This is what we call Immediately Invoked Function Expression (IIFE) or Self Executing Anonymous Function.SyntaxHere’s the syntax −(function() {    // code })();As you can see above, the following pair of parentheses converts the code inside the parentheses into an expression −function(){...}In addition, the next pair, i.e. the second pair of parentheses continues the operation. ... Read More

The Function() constructor expects any number of string arguments. The last argument is the body of the function - it can contain arbitrary JavaScript statements, separated from each other by semicolons.ExampleYou can try to run the following code to invoke a function with new Function Constructor −                    var func = new Function("x", "y", "return x*y;");          function multiplyFunction(){             var result;             result = func(15,35);             document.write ( result );          }                     Click the following button to call the function