Error Javascript Object
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Javascript Error Handling
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Javascript Error Object Expected
History Print this article MDN Web technology For developers JavaScript JavaScript reference Standard built-in objects Error Your Search Results ariyankhan josephmcasey AlexanderFradiani fscholz mondwan SphinxKnight janosch-x davidchase Mingun shawnacscott Sheppy ethertank Nickolay evilpie trevorh teoli davidbourguignon secoif DomenicDenicola dgchurchill timemachine3030 Sevenspade Potappo Sephr Brettz9 Mgjbot Allanbonadio Ptak82 JustinLudwig Error In This Article SyntaxParametersDescriptionError typesPropertiesMethodsError instancesPropertiesStandard propertiesVendor-specific extensionsMicrosoftMozillaMethodsExamplesThrowing a javascript exception object generic errorHandling a specific errorCustom Error TypesSpecificationsBrowser compatibilitySee also The Error constructor creates an error object. Instances of Error objects are thrown when runtime errors occur. The Error object can also be used as a base object for user-defined exceptions. See below for standard built-in error types. Syntax new Error([message[, fileName[, lineNumber]]]) Parameters message Optional. Human-readable description of the error. fileName Optional. The value for the fileName property on the created Error object. Defaults to the name of the file containing the code that called the Error() constructor. lineNumber Optional. The value for the lineNumber property on the created Error object. Defaults to the line number containing the Error() constructor invocation. Description Runtime errors result in new Error objects being created and thrown. This page documents the use of the Error object itself and its use as a constructor function. For a list of properties and methods inherited by Error instances, see Error.prototype. Error types Besides the generic Error constructor, there are six other core error constructors in JavaScript. For client-side exc
As promised, we're going to take a closer look at the Error object that gets passed into the catch clause to see just what we can extract from it in an event of an error. The Error object
Javascript Error Object Line Number
in all browsers support the following two properties: name: The name of the error,
Jscript Error Object
or more specifically, the name of the constructor function the error belongs to. message: A description of the error, with this description object expected error in javascript while calling a function varying depending on the browser. try{ document.body.filters[0].apply() } catch(e){ alert(e.name + "\n" + e.message) } Demo: Six possible values can be returned by the name property, which as mentioned correspond to the names of the error's https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Error constructors. They are: Error Name Description EvalError An error in the eval() function has occurred. RangeError Out of range number value has occurred. ReferenceError An illegal reference has occurred. SyntaxError A syntax error within code inside the eval() function has occurred. All other syntax errors are not caught by try/catch/finally, and will trigger the default browser error message associated with the error. To catch actual syntax errors, you may use the onerror http://www.javascriptkit.com/javatutors/trycatch2.shtml event. TypeError An error in the expected variable type has occurred. URIError An error when encoding or decoding the URI has occurred (ie: when calling encodeURI()). This level of detail may be useful when you wish to sniff out a specific type of error in your catch clause. In the below, no DIV on the page exists with ID="mydiv". When trying to set its .innerHTML property, a TypeError occurs, since we're trying to assign the .innerHTML property to a null object: try{ document.getElementById("mydiv").innerHTML='Success' //assuming "mydiv" is undefined } catch(e){ if (e.name.toString() == "TypeError"){ //evals to true in this case //do something } } Ok, so maybe it's not that useful most of the time, but you just never know. Throwing your own errors (exceptions) Instead of waiting for one of the 6 types of errors above to occur before control is automatically transferred from the try block to the catch block, you can also explicitly throw your own exceptions to force that to happen on demand. This is great for creating your own definitions of what an error is and when control should be transferred to catch. To throw an error, invoke, well, the throw statement inside your try/catch/finally blocks. The syntax is: throw myerrorobject Where myerrorobject can in fact be anything from a string,
here for a quick overview of the site Help Center Detailed answers to any questions you might have Meta Discuss the workings and policies of this site About Us Learn more about Stack Overflow the company Business Learn more about hiring http://stackoverflow.com/questions/9156176/what-is-the-difference-between-throw-new-error-and-throw-someobject-in-javas developers or posting ads with us Stack Overflow Questions Jobs Documentation Tags Users Badges Ask Question x Dismiss Join the Stack Overflow Community Stack Overflow is a community of 4.7 million programmers, just like you, helping each other. Join http://www.w3schools.com/js/js_errors.asp them; it only takes a minute: Sign up What is the difference between `throw new Error` and `throw someObject` in JavaScript? up vote 120 down vote favorite 28 I want to write a common error handler which will catch javascript error custom errors thrown on purpose at any instance of the code. When I did throw new Error('sample') like in the following code try { throw new Error({'hehe':'haha'}); // throw new Error('hehe'); } catch(e) { alert(e); console.log(e); } Log shows in Firefox as Error: [object Object] and I couldn't parse the object. For the second throw the log shows as: Error: hehe Whereas when I did try { throw ({'hehe':'haha'}); } catch(e) { alert(e); console.log(e); } the console showed as: javascript error object Object { hehe="haha"} in which I was able to access the error properties. What is the difference? Is the difference as seen in the code? Like string will be just passed as string and object as objects but the syntax will be different? I haven't explored throwing error object... I had done only throwing strings. Is there any other way than the above two mentioned methods? javascript object error-handling exception-handling throw share|improve this question edited Jun 9 at 17:27 Bergi 217k19227371 asked Feb 6 '12 at 6:07 Jayapal Chandran 2,52984880 2 The problem with throw new Error({prop:val}) is that's not a valid construction of Error. Error has known properties as discussed by Hemant. –grantwparks May 14 '13 at 15:32 related: Throwing strings instead of Errors –Bergi Jun 9 at 17:28 add a comment| 3 Answers 3 active oldest votes up vote 93 down vote accepted here is a good explanation about The Error object and throwing your own errors The Error Object just what we can extract from it in an event of an error. The Error object in all browsers support the following two properties: name: The name of the error, or more specifically, the name of the constructor function the error belongs to. message: A description of the error, with this description varying depending on the browser. Six possible values can be returned by the name property, which as
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