Javascript Is Undefined Error
Contents |
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 undefined javascript check about Stack Overflow the company Business Learn more about hiring developers or posting ads javascript runtime error '$' is undefined mvc with us Stack Overflow Questions Jobs Documentation Tags Users Badges Ask Question x Dismiss Join the Stack Overflow Community Stack Overflow 0x800a1391 - javascript runtime error '$' is undefined jquery is a community of 4.7 million programmers, just like you, helping each other. Join them; it only takes a minute: Sign up '$' is undefined javascript error up vote 2 down vote favorite 1 this is a sample javascript code i got regarding drag and drop of images in a asp.net webpage...But javascript runtime error function is undefined it returns a error stating '$' is undefined..please help me out jquery asp.net share|improve this question edited Nov 11 '11 at 9:59 asked Nov 11 '11 at 9:51 Karthik 1,7061645 Are you sure you have included jQuery library correct? –janhartmann Nov 11 '11 at 9:52 1 It looks like the code is using jQuery, and jQuery UI. You'll need to download and include them both before your code. –James Allardice Nov 11 '11 at 9:53 An obvious first check: have you included jQuery in your page? The $ variable isn't stock JavaScript, it's jQuery –Zruty Nov 11 '11 at 9:53 1 It does not make sense to call document.getElementBydId() when you already use a JS CSS-selector framework like jQuery. $('#xpos).val(position.left - imgPosition.left) will do the same –Maxim Krizhanovsky Nov 11 '11 at 9:54 add a comment| 3 Answers 3 active oldest votes up vote 5 down vote accepted At a guess, I'd say you were missing the library to support that script (probably jQuery). You need to include a reference to the JavaScript framework in order to get the draggable functionality you're looking for. Try adding the following to your page (before the script block in your example):
("x is not defined") and how best to code against them can be frustrating. This is my attempt to straighten things out a little. If you're not already familiar with the difference between variables and properties in JavaScript (including the internal VariableObject) now might javascript runtime error '$' is undefined visual studio be a good time to check out my previous posting. What is undefined? In
Javascript Runtime Error '$' Is Undefined C#
JavaScript there is Undefined (type), undefined (value) and undefined (variable). Undefined (type) is a built-in JavaScript type. undefined (value) is a primitive
Javascript Function Return Undefined
and is the sole value of the Undefined type. Any property that has not been assigned a value, assumes the undefined value. (ECMA 4.3.9 and 4.3.10). A function without a return statement, or a function with http://stackoverflow.com/questions/8092226/is-undefined-javascript-error an empty return statement returns undefined. The value of an unsupplied function argument is undefined. var a; typeof a; //"undefined" window.b; typeof window.b; //"undefined" var c = (function() {})(); typeof c; //"undefined" var d = (function(e) {return e})(); typeof d; //"undefined" undefined (variable) is a global property whose initial value is undefined (value), Since its a global property we can also access it as a variable. For consistency I'm always going to call https://javascriptweblog.wordpress.com/2010/08/16/understanding-undefined-and-preventing-referenceerrors/ it a variable in this article. typeof undefined; //"undefined" var f = 2; f = undefined; //re-assigning to undefined (variable) typeof f; //"undefined" As of ECMA 3, its value can be reassigned : undefined = "washing machine"; //assign a string to undefined (variable) typeof undefined //"string" f = undefined; typeof f; //"string" f; //"washing machine" Needless to say, re-assigning values to the undefined variable is very bad practice, and in fact its not allowed by ECMA 5 (though amongst the current set of full browser releases, only Safari enforces this). And then there's null? Yes, generally well understood but worth re-stating: undefined is distinct from null which is also a primitive value representing the intentional absence of a value. The only similarity between undefined and null is they both coerce to false. So what's a ReferenceError? A ReferenceError indicates that an invalid reference value has been detected (ECMA 5 15.11.6.3) In practical terms, this means a ReferenceError will be thrown when JavaScript attempts to get the value of an unresolvable reference. (There are other cases where a ReferenceError will be thrown, most notably when running in ECMA 5 Strict mode. If you're interested check the reading list at the end of this article) Note how the message syntax varies across browser. As we will see none
Learn Bootstrap Learn Graphics Learn Icons Learn How To JavaScript Learn JavaScript Learn jQuery Learn jQueryMobile Learn AppML Learn AngularJS Learn JSON Learn AJAX Server Side Learn SQL Learn PHP Learn ASP Web Building Web Templates Web Statistics Web Certificates XML Learn XML http://www.w3schools.com/js/js_mistakes.asp Learn XML AJAX Learn XML DOM Learn XML DTD Learn XML Schema Learn XSLT Learn XPath Learn XQuery × HTML HTML Tag Reference HTML Event Reference HTML Color Reference HTML Attribute Reference HTML Canvas Reference HTML SVG Reference Google Maps Reference CSS CSS Reference CSS Selector Reference W3.CSS Reference Bootstrap Reference Icon Reference JavaScript JavaScript Reference HTML DOM Reference jQuery Reference jQuery Mobile Reference AngularJS Reference XML XML Reference XML Http Reference XSLT Reference XML Schema Reference is undefined Charsets HTML Character Sets HTML ASCII HTML ANSI HTML Windows-1252 HTML ISO-8859-1 HTML Symbols HTML UTF-8 Server Side PHP Reference SQL Reference ASP Reference × HTML/CSS HTML Examples CSS Examples W3.CSS Examples Bootstrap Examples JavaScript JavaScript Examples HTML DOM Examples jQuery Examples jQuery Mobile Examples AngularJS Examples AJAX Examples XML XML Examples XSLT Examples XPath Examples XML Schema Examples SVG Examples Server Side PHP Examples ASP Examples Quizzes HTML Quiz CSS Quiz JavaScript Quiz Bootstrap Quiz jQuery javascript runtime error Quiz PHP Quiz SQL Quiz XML Quiz × JS Tutorial JS HOME JS Introduction JS Where To JS Output JS Syntax JS Statements JS Comments JS Variables JS Operators JS Arithmetic JS Assignment JS Data Types JS Functions JS Objects JS Scope JS Events JS Strings JS String Methods JS Numbers JS Number Methods JS Math JS Random JS Dates JS Date Formats JS Date Methods JS Arrays JS Array Methods JS Array Sort JS Booleans JS Comparisons JS Conditions JS Switch JS Loop For JS Loop While JS Break JS Type Conversion JS RegExp JS Errors JS Debugging JS Hoisting JS Strict Mode JS Style Guide JS Best Practices JS Mistakes JS Performance JS Reserved Words JS JSON JS Forms JS Forms Forms API JS Objects Object Definitions Object Properties Object Methods Object Prototypes JS Functions Function Definitions Function Parameters Function Invocation Function Closures JS HTML DOM DOM Intro DOM Methods DOM Document DOM Elements DOM HTML DOM CSS DOM Animations DOM Events DOM EventListener DOM Navigation DOM Nodes DOM Nodelist JS Browser BOM JS Window JS Screen JS Location JS History JS Navigator JS Popup Alert JS Timing JS Cookies JS JSON JSON Intro JSON Syntax JSON HowTo JSON Http JSON Files JSON SQL JS Examples JS Examples JS HTML DOM JS HTML Input JS HTML Objects JS HTML Events JS Browser JS Quiz JS Certificate JS Re