JavaScript

When accessing a web site, the browser needs to load all the files during the first visit. This mainly depends on the server performance, bandwidth, and server cache settings, during the second visit, we can use the client browser cache to store

I. Concepts Function: similar to the constructor, the initialization block can also initialize Java objects. Nature: it is the 4th types of members (Field, method, and constructor) that can appear in the Java class. It has no name or identifier,

Equals is a method in the Object class. Determine whether the two objects are the same. Defined as x. queals (y). If x and y are the same object, true is returned. Otherwise, false is returned. J2set provides classes that overwrite the queal usage

Copy codeThe Code is as follows:$ ("Ancestor descendant"): select the child element after the parent Element$ ("Parent> child"): select the child element directly following the parent element. What is "directly", that is, the meaning of the first

Method for defining Regular Expressions There are two ways to define a regular expression: constructor definition and regular expression definition. For example: The Code is as follows:   Var reg1 = new RegExp ('d {5, 11}

1. What is a deferred object? During website development, we often encounter some javascript operations that take a long time. Both asynchronous operations (for example, ajax reading server data) and synchronous operations (for example, traversing a

There are two ways to create, both of which are the methods provided by global object Qt. I. Use Qt. createComponent to load a qml file and create Component Ii. Use Qt. createQmlObject to create Component from a qml string Note that the above two

Ext JS 4 require Dynamic Loading Loading all js files at a time is inefficient for large projects. It may only be a simple homepage, but it may take several or even dozens of seconds to get out. Can I load it as needed? Dynamic Loading is a new

If you are still worried about the opacity of the background transparent text, we suggest you take a look. Of course, IE6 has been abandoned, so do not say that the PNG8 image is ineffective in IE6. Of course, you can also use a filter. I do not

Parent window:Copy codeThe Code is as follows: No title page Subwindow:Copy codeThe Code is as follows: No title page ---- 1. Basic syntax ---- The window object has a method called showModalDialog. We can write the following code in onclick of the

The window. history Object does not use the window prefix when writing. To protect user privacy, the methods for accessing this object by JavaScript are limited. Method: History. back ()-load the previous URL in the history list, which is the same

A floating point error occurs during the fractional Multiplication operation in JS. You can test the problem as follows: The result is 251.89999999999998 instead of 251.9. This problem may be a headache for many people. How can this problem be

1. Discard the fractional part and retain the integer part.ParseInt (5/2) 2. rounded up. If there is a decimal number, add 1 to the integer part. Math. ceil (5/2) 3. rounding. Math. round (5/2) 4. Round down Math. floor (5/2) Math object

Copy codeThe Code is as follows:Switch (objNameType ){ Case 'pd ': ValueUD = obj. id; Id = objName; Var loadVUD = UserData. load (exam, id ); If (loadVUD = null | loadVUD = undefined | loadVUD = ''){ Var tmpTGId = obj. id. substr (0, obj. id.

Bootstrap is an open-source toolkit for front-end development. It was developed by Twitter designer Mark Otto and Jacob Thornton. It is a CSS/HTML framework. Bootstrap provides elegant HTML and CSS specifications, which are written by the dynamic

(1) required: required field for true(2) remote: "check. php" uses ajax to call check. php to verify the input value.(3) email: true: You must enter an email in the correct format.(4) url: true must enter the url in the correct format(5) date: true

There are many methods for determining the browser and version on the Internet. Here, the younger brother sums up one or two to save everyone's time.1. jquery method: Regular Expressions can be used to determine common browsers and their

Why use js to get the uploaded file name? In fact, it is purely for beautification and friendliness,However, this is not the case on the Internet. Use path. substring (path. lastIndexOf ('/') + 1 );This may cause many problems at work.For example,

How to copy an object in js, such as the next js object.If you know all the attributes of this object, you can naturally create a new one, and then assign values to each attribute, you can do it, but if you do not know? How to create an object with

1. Create an arrayCopy codeThe Code is as follows:Var array = new Array ();Var array = new Array (size); // specify the length of the arrayVar array = new Array (item1, item2 ...... ItemN); // create an array and assign values 2. value and value