General events | ||
---|---|---|
Event | Browser support | Description |
onClick | HTML: 2 | 3 | 3.2 | 4 Browser: IE3 | N2 | O3 |
Mouse click event, mostly used for mouse clicks within the range controlled by an object |
onDblClick | HTML: 2 | 3 | 3.2 | | O
Mouse double click event onMouseDown | HTML: 2 | 3 | 3.2 | | O |
onMouseUp |
HTML: 2 | 3 | 3.2 | | O Events fired when the mouse is pressed and released onMouseOver |
|
4 Browser: | IE3
| N2 | O3 Event triggered when the mouse moves over the range of an object |
|
HTML: 2 | 3 | 3.2 | | O | Events triggered when the mouse moves
onMouseOut HTML: 2 | 3 | 3.2 | | O3 | Event triggered when the mouse leaves the scope of an object|
onKeyPress | HTML: 2 | 3 | 3.2 |
| O
An event triggered when a key on the keyboard is pressed and released. [Note: There must be a focused object in the page] onKeyDown HTML: 2 | 3 | 3.2 | |
| O |
onKeyUp |
HTML: 2 | 3 | 3.2 | | O Event triggered when a key on the keyboard is pressed and released [Note: There must be a focused object in the page] Page related events |
Event |
Browser support | Description | |
onAbort | HTML: 2 | 3 | 3.2 | 4 Browser: IE4 | N3 | O |
Image was interrupted by user while downloading |
onBeforeUnload | HTML: 2 | 3 | 3.2 | 4 Browser: IE4 | N | O |
Event triggered when the content of the current page is about to be changed |
onError | HTML: 2 | 3 | 3.2 | 4 Browser: IE4 | N3 | O |
Capture errors that occur on the current page for some reason, such as script errors and external data reference errors |
onLoad | HTML: 2 | 3 | 3.2 | 4 Browser: IE3 | N2 | O3 |
Events triggered when the page is empty and transferred to the browser, including the completion of external file introduction |
onMove | HTML: 2 | 3 | 3.2 | 4 Browser: IE | N4 | O |
Event triggered when the browser window is moved |
onResize | HTML: 2 | 3 | 3.2 | 4 Browser: IE4 | N4 | O |
Event triggered when the browser window size is changed |
onScroll | HTML: 2 | 3 | 3.2 | 4 Browser: IE4 | N | O |
Event triggered when the browser's scroll bar position changes |
onStop | HTML: 2 | 3 | 3.2 | 4 Browser: IE5 | N | O |
Event triggered when the browser's stop button is pressed or the file being downloaded is interrupted |
onUnload | HTML: 2 | 3 | 3.2 | 4 Browser: IE3 | N2 | O3 |
Event triggered when the current page will be changed |
Form related events | ||
Event | Browser support | Description |
onBlur | HTML: 2 | 3 | 3.2 | 4 Browser: IE3 | N2 | O3 |
Event triggered when the current element loses focus [can be triggered by mouse and keyboard] |
onChange | HTML: 2 | 3 | 3.2 | 4 Browser: IE3 | N2 | O3 |
Events triggered when the current element loses focus and the content of the element changes [can be triggered by mouse and keyboard] |
onFocus | HTML: 2 | 3 | 3.2 | 4 Browser: IE3 | N2 | O3 |
Event triggered when an element gets focus |
onReset | HTML: 2 | 3 | 3.2 | | O3 Event triggered when the RESET attribute in the form is fired onSubmit | HTML: 2 | 3 | 3.2 |4 |
Browser: IE3 | | N2 | O3 An event triggered when a form is submitted Rolling subtitle event |
|
Browser support | ||
Description | onBounce | HTML: 2 | 3 | 3.2 | 4 Browser: |
| N | O Event triggered when the content in Marquee moves outside the display range of Marquee |
onFinish | HTML: 2 | 3 | 3.2 | 4 Browser: |
| N | O Event triggered when the Marquee element completes the content that needs to be displayed |
onStart | HTML: 2 | 3 | 3.2 | 4 Browser: |
| N | O Event triggered when the Marquee element starts displaying content |
Edit event |
|
Browser support | ||
Description | onBeforeCopy | HTML: 2 | 3 | 3.2 | 4 Browser: |
| N | O Event triggered before the currently selected content of the page is to be copied to the viewer's system clipboard |
onBeforeCut | HTML: 2 | 3 | 3.2 | 4 Browser: |
| N | O Event triggered when part or all of the content in the page will be moved away from the current page [clip] and moved to the viewer's system clipboard |
onBeforeEditFocus | HTML: 2 | 3 | 3.2 | 4 Browser: |
| N | O The current element will enter the editing state |
onBeforePaste | HTML: 2 | 3 | 3.2 | 4 Browser: |
| N | O Event triggered when content is about to be transferred [pasted] from the viewer's system clipboard to the page |
onBeforeUpdate | HTML: 2 | 3 | 3.2 | 4 Browser: |
| N | O Notify target audience when a viewer pastes content from the system clipboard |
onContextMenu | HTML: 2 | 3 | 3.2 | 4 Browser: |
| N | O | Events triggered when the browser presses the right mouse button to display the menu or when the page menu is triggered by keyboard keys [Try adding onContentMenu="return false" to on the page to disable the use of the right mouse button ] | |
onCopy | HTML: 2 | 3 | 3.2 | 4 Browser: IE5 | N | O |
Event triggered when the currently selected content on the page is copied |
onCut | HTML: 2 | 3 | 3.2 | 4 Browser: IE5 | N | O |
Event triggered when the currently selected content on the page is cut |
onDrag | HTML: 2 | 3 | 3.2 | 4 Browser: IE5 | N | O |
Event triggered when an object is dragged [Activity event] |
onDragDrop | HTML: 2 | 3 | 3.2 | 4 Browser: IE | N4 | O |
An external object is dragged into the current window or frame by the mouse |
onDragEnd | HTML: 2 | 3 | 3.2 | 4 Browser: IE5 | N | O |
Event triggered when the mouse drag ends, that is, the mouse button is released |
onDragEnter | HTML: 2 | 3 | 3.2 | 4 Browser: IE5 | N | O |
Event triggered when the object dragged by the mouse enters its container scope |
onDragLeave | HTML: 2 | 3 | 3.2 | 4 Browser: IE5 | N | O |
Event triggered when the object dragged by the mouse leaves the scope of its container |
onDragOver | HTML: 2 | 3 | 3.2 | 4 Browser: IE5 | N | O |
Event triggered when a dragged object is dragged within the scope of another object container [Activity event] |
onDragStart | HTML: 2 | 3 | 3.2 | 4 Browser: IE4 | N | O |
Event triggered when an object is to be dragged |
onDrop | HTML: 2 | 3 | 3.2 | 4 Browser: IE5 | N | O |
During a dragging process, an event is triggered when the mouse button is released |
onLoseCapture | HTML: 2 | 3 | 3.2 | 4 Browser: IE5 | N | O |
Event triggered when an element loses the selection focus formed by mouse movement |
onPaste | HTML: 2 | 3 | 3.2 | 4 Browser: IE5 | N | O |
Event triggered when content is pasted |
onSelect | HTML: 2 | 3 | 3.2 | 4 Browser: IE4 | N | | Event when text content is selected|
onSelectStart | HTML: 2 | 3 | 3.2 | 4Browser: IE4 | N | O |
Event triggered when text content selection will start to occur |
Data Binding | ||
Event | Browser support | Description |
onAfterUpdate | HTML: 2 | 3 | 3.2 | 4 Browser: IE4 | N | O |
Event triggered when data completes transfer from data source to object |
onCellChange | HTML: 2 | 3 | 3.2 | 4 Browser: IE5 | N | O |
When the data source changes |
onDataAvailable | HTML: 2 | 3 | 3.2 | 4 Browser: IE4 | N | O |
Event triggered when data reception is completed |
onDatasetChanged | HTML: 2 | 3 | 3.2 | 4 Browser: IE4 | N | O |
Events triggered when the data source changes |
onDatasetComplete | HTML: 2 | 3 | 3.2 | 4 Browser: IE4 | N | O |
Event triggered when all valid data from the sub-data source is read |
onErrorUpdate | HTML: 2 | 3 | 3.2 | 4 Browser: IE4 | N | O |
When the data transfer is canceled using the onBeforeUpdate event trigger, replace the onAfterUpdate event |
onRowEnter | HTML: 2 | 3 | 3.2 | 4 Browser: IE5 | N | O |
Events triggered when the data in the current data source changes and there is new valid data |
onRowExit | HTML: 2 | 3 | 3.2 | 4 Browser: IE5 | N | O |
Event triggered when the data of the current data source is about to change |
onRowsDelete | HTML: 2 | 3 | 3.2 | 4 Browser: IE5 | N | O |
Event triggered when the current data record will be deleted |
onRowsInserted | HTML: 2 | 3 | 3.2 | 4 Browser: IE5 | N | O |
Event triggered when the current data source is about to insert a new data record |
External events | ||
Event | Browser support | Description |
onAfterPrint | HTML: 2 | 3 | 3.2 | 4 Browser: IE5 | N | O |
Event triggered when the document is printed |
onBeforePrint | HTML: 2 | 3 | 3.2 | 4 Browser: IE5 | N | O |
Event triggered when the document is about to be printed |
onFilterChange | HTML: 2 | 3 | 3.2 | 4 Browser: IE4 | N | O |
Event triggered when the filter effect of an object changes |
onHelp | HTML: 2 | 3 | 4 브라우저: IE4 | 시청자가 F1을 누르거나 브라우저 도움말을 선택할 때 발생하는 이벤트 |
속성변경 | HTML: 2 | 3 | 3.2 | 4브라우저: IE5 객체의 속성 중 하나가 변경될 때 발생하는 이벤트 |
|
onReadyStateChange HTML: 2 | 3 | 4 | 브라우저:
IE4 객체의 초기화 속성 값이 변경될 때 발생하는 이벤트 |

JavaScript's application in the real world includes front-end and back-end development. 1) Display front-end applications by building a TODO list application, involving DOM operations and event processing. 2) Build RESTfulAPI through Node.js and Express to demonstrate back-end applications.

The main uses of JavaScript in web development include client interaction, form verification and asynchronous communication. 1) Dynamic content update and user interaction through DOM operations; 2) Client verification is carried out before the user submits data to improve the user experience; 3) Refreshless communication with the server is achieved through AJAX technology.

Understanding how JavaScript engine works internally is important to developers because it helps write more efficient code and understand performance bottlenecks and optimization strategies. 1) The engine's workflow includes three stages: parsing, compiling and execution; 2) During the execution process, the engine will perform dynamic optimization, such as inline cache and hidden classes; 3) Best practices include avoiding global variables, optimizing loops, using const and lets, and avoiding excessive use of closures.

Python is more suitable for beginners, with a smooth learning curve and concise syntax; JavaScript is suitable for front-end development, with a steep learning curve and flexible syntax. 1. Python syntax is intuitive and suitable for data science and back-end development. 2. JavaScript is flexible and widely used in front-end and server-side programming.

Python and JavaScript have their own advantages and disadvantages in terms of community, libraries and resources. 1) The Python community is friendly and suitable for beginners, but the front-end development resources are not as rich as JavaScript. 2) Python is powerful in data science and machine learning libraries, while JavaScript is better in front-end development libraries and frameworks. 3) Both have rich learning resources, but Python is suitable for starting with official documents, while JavaScript is better with MDNWebDocs. The choice should be based on project needs and personal interests.

The shift from C/C to JavaScript requires adapting to dynamic typing, garbage collection and asynchronous programming. 1) C/C is a statically typed language that requires manual memory management, while JavaScript is dynamically typed and garbage collection is automatically processed. 2) C/C needs to be compiled into machine code, while JavaScript is an interpreted language. 3) JavaScript introduces concepts such as closures, prototype chains and Promise, which enhances flexibility and asynchronous programming capabilities.

Different JavaScript engines have different effects when parsing and executing JavaScript code, because the implementation principles and optimization strategies of each engine differ. 1. Lexical analysis: convert source code into lexical unit. 2. Grammar analysis: Generate an abstract syntax tree. 3. Optimization and compilation: Generate machine code through the JIT compiler. 4. Execute: Run the machine code. V8 engine optimizes through instant compilation and hidden class, SpiderMonkey uses a type inference system, resulting in different performance performance on the same code.

JavaScript's applications in the real world include server-side programming, mobile application development and Internet of Things control: 1. Server-side programming is realized through Node.js, suitable for high concurrent request processing. 2. Mobile application development is carried out through ReactNative and supports cross-platform deployment. 3. Used for IoT device control through Johnny-Five library, suitable for hardware interaction.


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