CSS Master

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Abetterapproach,however—particularlyifyoustillneedtosupportInternetEx-

plorer 8 —istoaddtheless-thanorequal-tooperator:

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ConditionalcommentsaredeprecatedinInternetExplorer10+;theyaren’tavailable

instandardsmode.Thatbringsustoourotherapproach.

Using CSS Parsing to Our Advantage

AnotherapproachtosupportingolderbrowsersisinherenttoCSS.Wecantake

advantageofCSSerrorhandlingandthecascadetodefinestylesforolderbrowsers.

ThismethodreliesontworulesofCSSparsing:

1.Thelastdeclarationparsedistheonethat’sused.

2.Ifabrowserfailstounderstandarule,itwillignoreit.

Inotherwords,wecanprovideafallbackvalueandanenhancedvalueforaproperty.

Thebrowserwillchoosewhichtoimplementbasedonwhatitsupports.Here’san

example:

.title {

text-decoration: underline;

text-decoration: underline wavy #c09;

}

InbrowsersthatsupportCSS 3 text-decorationvalues,userswillseeawavypink

lineunderelementswiththetitleclass;inbrowserswithoutsupport,they’llsee

aplainunderline.TheserulescanexistwithinthesameCSSfileanddeclaration

block,butyoumaydecidetosegregatelegacyrulesintheirownfilesothatthey

canberemovedasyouraudienceadoptsnewerbrowsers.

Nowthatwe’vediscussedthebasicsofCSSfilestructureandlegacybrowserman-

agement,let’slookatsomeCSSarchitecturetechniques.

76 CSS Master