CRM Summary 2

1. The difference between pre-compilation and character stitching:

precompilation prevents SQL injection, but does not handle the% and _ special characters. (so-called SQL injection, that is, by inserting SQL commands into the Web form to submit or enter a domain name or page request query string, eventually to deceive the server to execute malicious SQL commands, such as many of the previous film and television sites leaked VIP membership password is mostly through the Web form to submit the query character burst out, Such forms are particularly susceptible to SQL injection attacks. ）

2. What are the positioning?

Static positioning: Formatted in the order of the document flow;

Relative positioning: Relative to the original space offset in the document flow;

Absolute positioning: Out of normal document flow, space is not preserved, relative to the nearest non-static parent element is positioned;

Fixed positioning: Detached from the document stream and positioned relative to the viewport.

3. What are the methods to clear the float?

1), Clear:both;

2), Overflow:hidden;

3), after which an empty block-level element is added;

4), using after pseudo elements #outer:after{content: ".";  height:0; Visibility:hidden;

Display:block; Clear:both; }

4, BFC Generation mode

1), float for left | Right

2), overflow for hidden| Auto| Scroll

3), display for Table-cell| table-caption| Inline-block

4), Position for Absolute| fixed

5. Node value of element node: null

6, CloneNode () deep cloning and shallow cloning difference:

The difference between deep clones and shallow clones is that shallow clones only clone normal properties and do not clone object properties. Deep clones are cloned together with object properties.

7. What are the CSS boxes?

Em, content area, embedded box, line box

8. JS Technology system: JS core language definition, OST object and built-in object, browser object model, Document Object model, event processing model

9, too much text display ellipsis: Text-overflow:ellipsis.

10, HTML Full name: Hypertext Markeup Language.

11, two array add: a1=[1,2],a2=[3,4], display the result: [1,23,4].

CRM Summary 2