Analysis of three positioning schemes in CSS 2.1_html/css_WEB-ITnose

Normal flow (NormalFlow Float must be positioned AbsolutPosit 1. What is block formatting context With the above knowledge, you can introduce Blockformatcontext block formatting context) Created the BlockFormatContext element , its child elements will be placed one after another. The vertical starting point is the top of a containing block, and the vertical distance between two adjacent elements depends on the 'margin' property. The straight margins of adjacent block-level elements in BlockFormatContext will collapse (collaps throotelementorsomeththatcontainitfloatelementwherefloatisnotnoneabsolutpositelementelementwherepositisabsolutorfixinline-blockelementwithdisplay:inline-blocktablcellelementwithdisplay:table-cell,whichisthedefaultforHTMLtablcelltablcaptionelementwithdisplay:table-caption,whichisthedefaultforHTMLtabl captionelwhereoverflowhaavaluotherthanvisiblflexboxelementwithdisplay:flexorinline-flex

2 "overflow" value is not "visible" 4 "table-caption", or "inline-block" 3. BFC use 1BlockFormatContext can prevent margin collapsing (margincollaps