JavaScript reserved words
When coding with JavaScript, it will benefit you to know certain reserved words. The following list contains JavaScript reserved words. You can’t use these words as JavaScript variables, functions, methods, loop labels, or object names.
| abstract | final | public |
| boolean | finally | return |
| break | float | short |
| byte | for | static |
| case | function | super |
| catch | goto | switch |
| char | if | synchronized |
| class | implements | this |
| const | import | throw |
| continue | in | throws |
| debugger | instanceof | transient |
| default | int | true |
| delete | interface | try |
| do | long | typeof |
| double | native | var |
| else | new | void |
| enum | null | volatile |
| export | package | while |
| extends | private | with |
| false | protected |
List of HTML5 APIs for coding with JavaScript
Here is an extensive list of HTML5 APIs that have either been proposed or implemented. Browsers are constantly being updated with new features. For the latest on which browsers support which features, visit caniuse.com.
| API | What It Does |
|---|---|
| Ambient Light API | Provides information about the ambient light levels, as detected by a device’s light sensor. |
| Battery Status API | Provides information about the battery status of the device. |
| Canvas 2D Context | Allows drawing and manipulation of graphics in a browser. |
| Clipboard API | Provides access to the operating system’s copy, cut, and paste functionality. |
| Contacts | Allows access to a user’s contacts repository in the web browser. |
| Drag and Drop | Supports dragging and dropping items within and between browser windows. |
| File API | Provides programs with secure access to the device’s file system. |
| Forms | Gives programs access to the new data types defined in HTML5. |
| Fullscreen API | Controls the use of the user’s full screen for web pages, without the browser user interface. |
| Gamepad API | Supports input from USB gamepad controllers. |
| Geolocation | Provides web applications with access to geographical location data about the user’s device. |
| getUserMedia/Stream API | Provides access to external device data (such as webcam video). |
| History API | Allows programs to manipulate the browser history. |
| HTML Microdata | Provides a way to annotate content with computer-readable labels. |
| Indexed database | Creates a simple client-side database system in the web browser. |
| Internationalization API | Provides access to locale-sensitive formatting and string comparison. |
| Offline apps | Allows programmers to make web apps available in offline mode. |
| Proximity API | Provides information about the distance between a device and an object. |
| Screen Orientation | Reads the screen orientation state (portrait or landscape) and gives programmers the ability to know when it changes and to lock it in place. |
| Selection | Supports selecting elements in JavaScript using CSS-style selectors. |
| Server-sent events | Allows the server to push data to the browser without the browser needing to request it. |
| User Timing API | Gives programmers access to high-precision timestamps to measure the performance of applications. |
| Vibration API | Allows access to the vibration functionality of the device. |
| Web Audio API | API for processing and synthesizing audio. |
| Web Messaging | Allows browser windows to communicate with each other across different origins. |
| Web Speech API | Provides speech input and text-to-speech output features. |
| Web storage | Allows the storage of key-value pairs in the browser. |
| Web sockets | Opens an interactive communication session between the browser and server. |
| Web Workers | Allows JavaScript to execute scripts in the background. |
| XMLHttpRequest2 | Improves XMLHttpRequest to eliminate the need to work around the same-origin policy errors and to make XMLHttpRequest work with new features of HTML5. |
jQuery selectors for coding with JavaScript
JQuery provides many different ways to match sets of elements within a document beyond the methods built into JavaScript. Check out this list of all the jQuery selectors. To use them, simply pass them to the jQuery function (or, you can use the $ alias for the jQuery function). For example:
-
$(“*”) selects every element.
-
$(“div p:first-child”) selects the first paragraph child of each matched div element.
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$(“div:contains(‘We hold these truths’)”) selects the divs that contain the matching text.
Check here to see examples of each of these jQuery selectors inside programs.
| Selector | What It Selects |
|---|---|
| All Selector (“*”) | All elements. |
| :animated Selector | All elements that are animated at the time of selection. |
| Attribute Contains Prefix Selector [name|=”value”] | Elements that have the specified attribute with a value either equal to a given string or starting with that string followed by a hyphen (-). |
| Attribute Contains Selector [name*=”value”] | Elements that have the specified attribute with a value containing a given substring. |
| Attribute Contains Word Selector [name~=”value”] | Elements that have the specified attribute with a value containing a given word, delimited by spaces. |
| Attribute Ends With Selector [name$=”value”] | Elements that have the specified attribute with a value ending exactly with a given string. The comparison is case sensitive. |
| Attribute Equals Selector [name=”value”] | Elements that have the specified attribute with a value exactly equal to a certain value. |
| Attribute Not Equal Selector [name!=”value”] | Elements that either don’t have the specified attribute or do have the specified attribute but not with a certain value. |
| Attribute Starts With Selector [name^=”value”] | Elements that have the specified attribute with a value beginning exactly with a given string. |
| :button Selector | All button elements and elements of type button. |
| :checkbox Selector | Elements of type checkbox. |
| :checked Selector | All elements that are checked or selected. |
| Child Selector (“parent > child”) | All direct child elements specified by “child” of elements specified by “parent”. |
| Class Selector (“.class”) | Elements with the given class. |
| :contains() Selector | Elements that contain the specified text. |
| Descendant Selector (“ancestor descendant”) | Elements that are descendants of a given ancestor. |
| :disabled Selector | Elements that are disabled. |
| Element Selector (“element”) | Elements with the given tag name. |
| :empty Selector | Elements that have no children (including text nodes). |
| :enabled Selector | Elements that are enabled. |
| :eq() Selector | The element at index n within the matched set. |
| :even Selector | Even elements, zero-indexed. See also odd. |
| :file Selector | Elements of type file. |
| :first-child Selector | Elements that are the first child of their parent. |
| :first-of-type Selector | Elements that are the first among siblings of the same element name. |
| :first Selector | The first matched element. |
| :focus Selector | The element that is currently focused. |
| :gt() Selector | Elements at an index greater than index within the matched set. |
| Has Attribute Selector [name] | Elements that have the specified attribute, with any value. |
| :has() Selector | Elements which contain at least one element that matches the specified selector. |
| :header Selector | Elements that are headers, like h1, h2, h3, and so on. |
| :hidden Selector | Elements that are hidden. |
| ID Selector (“#id”) | A single element with the given id attribute. |
| :image Selector | Elements of type image. |
| :input Selector | All input, textarea, select, and button elements. |
| :lang() Selector | Elements of the specified language. |
| :last-child Selector | Elements that are the last child of their parent. |
| :last-of-type Selector | Elements that are the last among siblings of the same element name. |
| :last Selector | The last matched element. |
| :lt() Selector | Elements at an index less than index within the matched set. |
| Multiple Attribute Selector [name=”value”][name2=”value2″] | Elements that match all the specified attribute filters. |
| Multiple Selector (“selector1, selector2, selectorN”) |
The combined results of all the specified selectors. |
| Next Adjacent Selector (“prev + next”) | All next elements matching “next” that are immediately preceded by a sibling “prev”. |
| Next Siblings Selector (“prev ~ siblings”) | All sibling elements that follow after the “prev” element, have the same parent, and match the filtering “siblings” selector. |
| :not() Selector | Elements that do not match the given selector. |
| :nth-child() Selector | Elements that are the nth-child of their parent. |
| :nth-last-child() Selector | Elements that are the nth-child of their parent, counting from the last element to the first. |
| :nth-last-of-type() Selector | All the elements that are the nth-child of their parent in relation to siblings with the same element name, counting from the last element to the first. |
| :nth-of-type() Selector | Elements that are the nth child of their parent in relation to siblings with the same element name. |
| :odd Selector | Odd elements, zero-indexed. See also even. |
| :only-child Selector | Elements that are the only child of their parent. |
| :only-of-type Selector | Elements that have no siblings with the same element name. |
| :parent Selector | Elements that have at least one child node (either an element or text). |
| :password Selector | Elements of type password. |
| :radio Selector | Elements of type radio. |
| :reset Selector | Elements of type reset. |
| :root Selector | The element that is the root of the document. |
| :selected Selector | Elements that are selected. |
| :submit Selector | Elements of type submit. |
| :target Selector | The target element indicated by the fragment identifier of the document’s URI. |
| :text Selector | All input elements of type text. |
| :visible Selector | Elements that are visible. |