front end web developer nanodegree

CitationHttp://www.w3cplus.com/css/front-end-web-development-quiz.htmlQ7: What is the following code popup value?x = 1;function Bar () { this.x = 2; return x;} var foo = new bar (); alert (foo.x);Answer: 2Here the main problem is the definition of the outermost x, try to change the x=1 to x={}, the results will be different. What is this for? When using a f

1, Wiindow.onload and $ (document). The difference between readyWindow.onload can only appear once, $ (document). Ready can appear multiple timesWindow.onload needs to wait until all the files have been loaded before loading, $ (document). Ready just wait for the document structure to load and start loading2. What operations can cause memory leaks?A memory leak refers to any object that persists after it is no longer owned or needed(1) settimeout A memory leak when the first parameter is a strin

attributes (such as relative,absolute, etc.);3, remove the float.2. The second caseIE6, the level of performance is sometimes not to look at the z-index of the sub-tag, but to look at the hierarchy of the parent tag of the first relative property of the entire DOM tree.Eg:ie7 and IE6 have the same bug, the reason is very simple, although the image of the current level of the father of the div is very high (1000), but because Dad's father is not useful, poor 9999 such a strong child no doomed Ah

will be higher than the actual number of pixels; B, the content property is required, but its value can be null, blue ideal when discussing this method, the value of the Content property is set to "." again again: when an inner element is floating, the parent element will no longer contain the floating inner element if the float is not closed, because the floating element is out of the document flow. Which is why the outer layer cannot be stretched!Characteristics of floating:1. Floati

The first two semesters in fact always each semester to make a plan for themselves, but the plan is put into water, not oneself do not insist, only because the goal is too unclear, always do not see the effect, a period of time finally feel the plan to do, but not more than one months, to the plan to be meticulous to every week every day such effect is obvious, Think that they should not be passionate and willing to go to graduate school, simply graduation work, their own network or more interes

Date (); Dt.setseconds (Dt.getseconds () + 60); Document.cookie = "cookietest=1; Expires= "+ dt.togmtstring (); var cookiesenabled = document.cookie.indexOf ("cookietest=")!=-1; if (!cookiesenabled) {//No cookies enabled} 49. How to make cookies expire var date = new Date (); Date.settime (Date.gettime () + (x * 60 * 1000)); $.cookie (' Example ', ' foo ', {expires:date}); 50. How to use a clickable link to replace any URL in the page $.fn.replaceurl = function () {va

abstract browser inconsistency;4, always facing the set;5, the multiple operations based on one line; How do I download jquery? 1. Because JavaScript is an interpretive language, you don't have to worry about compiling and building. When you need to use jquery, just import it into your HTML document using the 2, jquery official website: http://jquery.com/ What are the development test tools? Modern browsers generally built-in high-quality development tools, we can choose the tools we find

Nonsense does not say more directly to everyone paste JS code. The specific code looks like this: The above is a small set to introduce the JS custom function of the Web front-end upload file type size judgment, I hope to help you, if you have any questions please give me a message, small series will promptly reply to everyone. Here also thank you ver

First, the principle of SQL injection attackThe attacker injects malicious SQL code into the HTTP request and executes it on the server.For example, user login, enter the user name Camille, password ' or ' 1 ' = ' 1, if you use the method of parameter construction, it will appearSelect * from User where = ' Camille ' and = "' or ' 1 ' = ' 1 'Regardless of the user name and password, the list of users queried is not empty, so you can look at the information of other users.Second, the defense of

Summary of Web Front-end interviews and summary of Web interviews2017web front-end interview Summary It has been more than half a year since I started the interview and written a written test in March to find an internship for sch

Repeated submission of web Front-end protection and repeated submission of web ProtectionPrevent repeated submission in front-end web development W