JavaScript

train of Thought HTML5 's canvas provides the Getimagedata interface to obtain the data in the canvas, so we can first draw the picture on the DrawImage with the canvas interface and then get the image data matrix by Getimagedata. Note that while

JavaScript often uses settimeout to postpone execution of a function, such as: Copy Code code as follows: settimeout (function () {alert ("Hello World");},1000); A delay of 1 seconds after execution to this sentence pops up

Preface In the previous article, we explained the changes in brightness and contrast in image processing, and this article we'll do a threshold function.The simplest method of image segmentation The threshold is the simplest method of image

One of the most frequently asked questions in a front-end interview is "What are some of the basic types of javascript?" ”。 Some answer "number, String, Boolean", some may add "Null, Undefined". And one might think that "object" is also a basic

JavaScript Window.confirm This method is very useful, you can pop up a confirmation dialog box The reason we pop up this dialog is because the operation is dangerous, so the user can confirm it. However, if you select OK by default, this principle

comparisons by value and by reference Numbers and Boolean values (True and false) are copied, passed, and compared by value. When copied or passed by value, a space is allocated in the computer's memory and the original value is copied to it. Then,

String Object 1, Str.match (REGEXP) Search for a matching regexp string in str and save it back in an array. If RegExp is not a global setting (/g), match only once Copy Code code as follows:

Objective Basically, all JS data types have both methods, except NULL. They both solve the problem of JavaScript value operations and display, and overrides increase the optimizations they invoke. Test analysis First look at one example:

Highcharts Official website: http://www.highcharts.com Highcharts Official Website Example: http://www.highcharts.com/demo/ Highcharts official website Document: Http://www.highcharts.com/documentation/how-to-use Official website example gives a

Array.prototype.push Push adds an item to the tail of the array and updates the length to return the array lengths. What happens if object uses push? Looking at the code below, obj works like an array. Length is automatically updated. Copy

If you are using the RESTful API now and you need to build a response to a JSON format string through a Web project, this article will help you use JavaScript to create a JSON format string. This is very useful and we will convert the data objects

I wrote a simple HTML5 Canvas chart Library, you can support pie, line, scatter, box diagram histogram, while supporting mouse prompts, drawing process animation effects. Finally, I want to put these multiple JS file into a JS file released, so my

Copy Code code as follows: javascript Implementation page Real-time display of current time

Positon:fixed the HTML element out of the document stream to a location in the browser There are often floating navigation bars in Web pages that use this positioning mode, but IE6 are not compatible with this positioning Floating navigation bar

Construction method Copy Code code as follows: function Coder () { this.name = ' modern Magic '; This.job = ' Web developer '; this.coding = function () {Alert (' I'm writing code ');} } var coder = new Coder

Detection of the existence of attributes in an object can be judged by several methods. 1. Use in keywordThis method can be used to determine whether an object's own properties and inherited properties exist. Copy Code code as follows:

Instance code see: Copy Code code as follows: 1 2 3 4 5 6 Effect: 12 3 4 5 6 [Ctrl + A All SELECT Note: If the need to introduce external JS need to refresh to perform] Instance

JS Set delay: Using setinterval and setting the delay function settimeout very similar. SetTimeout is used to delay a period of time and then perform an operation. SetTimeout ("function", time) sets a timeout object SetInterval ("function", time)

Before writing a JavaScript closure is what the article understanding closure, feel written very clearly, you can simply understand the cause of closure, but see comments are said to understand the scope chain and active objects to really understand

JavaScript randomly adds a picture from the first Dom to the second Div, which is a simple example of five images in the first div that extract the random two to display into the second Div. Copy Code code as follows: randomly