Questions on the web front face

Html+css 1. Understanding and knowledge of Web standards and websiteTag closure, label lowercase, no nesting, improve search robot search probability, use of external chain CSS and JS scripts, structure behavior of the separation, file download and page speed, content can be accessed by more users, content can be accessed by a wider range of devices, less code and components, easy maintenance, revision convenience, No need to change the content of the page, provide a print version without the need to copy content, improve the usability of the site;

What is the difference between 2.xhtml and HTML?HTML is a basic Web page design language, and XHTML is the main difference between an XML-based superscript language: XHTML elements must be nested correctly. XHTML elements must be closed. The label name must be in lowercase letters. The XHTML document must have a root element.

3.Doctype. Strict and promiscuous modes-how do you trigger these two patterns to differentiate between them?Used to declare documents using that specification (html/xhtml) is generally a strictly over-frame-based HTML document that joins an XML declaration that can be triggered and parsed to a bug that IE5.5 has IE5.5

4. What are the inline elements? What are block-level elements? CSS box model? Block-level elements: div p H1 H2 H3 h4 form UL inline elements: A b br i span input selectcss box model: Content, Border, margin,padding

What are the ways in which 5.CSS is introduced? What is the difference between link and @import?Inline inline outer chain import differences: Load the former without compatibility, the latter CSS2.1 the following browsers do not support link support using JavaScript to change the style, which is not

What are the 6.CSS selectors? Which properties can be inherited? How is the priority algorithm calculated? What is the high priority of inline and important? Tag Selector class Selector Id selector inheritance is not as good as specifying the id>class> label Select the latter priority

7. What are the three layers of the front page? What is the role? Structure Layer Html Presentation layer CSS behavior Layer JS

What is the basic statement composition of 8.CSS? Selector {Attribute 1: value 1; Property 2: Value 2; ...}

9. Which of the Web pages do you test? What are the cores of these browsers?IE (ie kernel) firefox (Gecko) Google (WebKit) opear (Presto)

10. How to solve several IE6 bugs1. Double-sided bug float caused by using display2.3 pixel problem using float-induced use dislpay:inline-3px 3. Hyperlinks hover After click fail to use the correct writing order link visited Hover Activ E4. Ie z-index problem add position:relative5 to parent. Png Transparent use JS code to change 6. Min-height min Height! Important Solution '
7.select hiding under IE6 use IFRAME nesting 8. Why there is no way to define a width container around 1px (IE6 the default row height, using over:hidden,zoom:0.08 line-height:1px)

11. What is the difference between the title and ALT attribute on the label? Alt when the picture is not displayed is represented by the text. Title provides information for this property

12. Describes the role and purpose of CSS reset. Reset the browser's CSS default properties browser for different symbols, different styles, and then reset them to unify

13. Explain CSS sprites, how to use it. The CSS Wizard consolidates a bunch of small images onto a large picture, reducing the number of requests to the server for pictures

14. What is the difference between browser standard mode and weird mode? The different use of the box model rendering mode Window.top.document.compatMode can show why the mode

15. How do you optimize your website's files and resources? The expected solutions include:File merge file minimization/file compression using CDN hosted cache usage

16. What is semantic HTML? Intuitive recognition tags are good for search engine crawling

17. Several ways to clear the float, the advantages and disadvantages of each1. Use empty tags to clear the floating clear:both (theoretically clear any label,, add meaningless labels) 2. Use Overflow:auto (empty label element to clear floating and have to increase the abuse of unintentional code, using zoom : 1 for compatible with IE) 3. To clear the float with Afert pseudo-elements (for non-IE browsers)

Javascript what data types are returned by the typeof of 1.javascriptObject number Function Boolean Underfind

2. Examples of 3 coercion type conversions and 2 implicit type conversions? Mandatory (parseint,parsefloat,number) implicit (= = = = = =)

3.split () The difference between join ()The former is the form of an array of cuts, the latter is the conversion of arrays into strings

4. Array method Pop () push () unshift () Shift ()Push () tail add pop () tail delete unshift () header add Shift () header Delete

5. What is the difference between event bindings and ordinary events?

Event bindings are events for DOM elements that are bound to DOM elements

Ordinary events are events that are not DOM-based elements

the difference between 6.IE and DOM event streams1. The order of execution is different, 2. The parameters are different. 3. Event Plus On4.this pointing problem

what is the compatibility of 7.IE and standard?Var ev = EV | | Window.eventdocument.documentElement.clientWidth | | Document.body.clientWidthVar target = ev.srcelement| | Ev.target

The difference between the Get and post modes when 8.ajax requestsOne is placed in the virtual carrier behind the URL there is a size limit security problem application is a forum, etc. only need to request, one is similar to change the password

the difference between 9.call and applyObject.call (THIS,OBJ1,OBJ2,OBJ3) object.apply (this,arguments)

how to interpret JSON data when 10.ajax requestsUse the Eval parse in view of security considerations using parse more reliable

11. Write a function that gets a non-inline style

function GetStyle (obj,attr,value)        {            if (!value)            {                if (Obj.currentstyle)                {                    return Obj.currentstyle (attr)                }                else                {                    Obj.getcomputedstyle (attr,false)                }            }            Else            {                obj.style[attr]=value            }        }

　　

12. What is the event delegate?Let's take advantage of the event bubbling principle, let your own trigger event, let his parent element instead of execution!

13. What are closures, what are the features, and what are the effects on the page?Closures are functions that can read other functions ' internal variables. http://blog.csdn.net/gaoshanwudi/article/details/7355794 This link can be viewed (not a company asking this question)

14. How to block event bubbling and default eventsCancebubble return False

15. Add Delete to replace the method inserted into a contactObj.appendchidl () Obj.innersetBeforeobj.replaceChildobj.removeChild

16. Explain the principles of JSONP, and why not the real AjaxDynamically create a script tag, callback function Ajax is a page no refresh request data operation

17.javascript local objects, built-in objects and host objectsLocal objects such as array obj regexp can be instantiated with a built-in object such as Gload Math, such as Document,window, which can not be instantiated by the browser.

the difference between 18.document load and document readyDocument.onload is executed after the structure and style are loaded jsdocument.ready native species do not have this method, jquery has $ (). Ready (function)

19. The difference between "= =" and "= = = "The former will automatically convert the type and the latter will not

Same -origin strategy for 20.javascriptA script can read only the properties of windows and documents from the same source, where the same source refers to a combination of host name, protocol, and port number

21. Write an array-to-weight method

function Osort (arr)        {            var result ={};             var newarr=[];              for (var i=0; I            {                if(!  Result[arr[i]]                {                    newarr.push (arr[i])                    Result[arr[i]]=1                }            }             return NEWARR        }

22. Sorting Algorithms

Quick Sort function Osort (arr) {if(arr.length<=1)            {                returnarr}varleft=[]; varright=[]; varOnum = Math.floor (ARR.LENGTH/2);varOnumvode = Arr.splice (onum,1);  for(varI=0; I {if(Arr[i] {left.push (arr[i])}Else{Right.push (Arr[i])}}returnOsort (left). Concat ([Onumvode],osort (right)}} bubble sortvarArray = [5, 4, 3, 2, 1];vartemp = 0; for(vari = 0; i < Array.Length; i++){ for(varj = 0; J < Array.length-i; J + +){if(Array[j] > array[j + 1]) {temp= Array[j + 1];array[j+ 1] =Array[j];array[j]=temp; }}}

Questions on the web front face