N'chifukwa chiyani tiyenera ndi mmene kulemba jQuery-selector?

Modern ukonde mlengi ayenera osati amaphunzira ndizosowa HTML ndi, ndi CSS ndi JavaScript, komanso kugwira ntchito mu laibulale jQuery, yomwe imayang'ana mogwirizana kwa JavaScript ndi-zikalata HTML. Kuti timatha kupeza mwamsanga mbali iliyonse ufumu (mawonekedwe ntchito mapulogalamu amene amapereka mwayi kwa okhutira owona HTML-) ndi kusintha iwo. Waukulu mayunitsi structural laibulale ndi timu. Pofuna ntchito limodzi kapena gulu zina, muyenera jQuery-selector.

Chilinganizo selectors mu jQuery laibulale

The selectors mu jQuery zochokera ntchito CSS. Iwo ayenera kusankha zinthu HTML-file, kuti ntchito chifukwa izi kapena njira zina zikugwira iwo (gulu). Search ikuchitika kudzera selector $ () ntchito. Mwachitsanzo, $ ( 'div').

selectors akhoza wachinsinsi malinga ndi mmene kusankha zinthu:

• zazikulu;
• ndi lingaliro;
• utsogoleri wolowezana;
• okhutira;
• pa zinthu;
• Kusankha m'minda mawonekedwe;
• ena.

selectors Ofunika

90% milandu ntchito laibulale ntchito jQuery-selector a gulu lalikulu. Onsewo ndi wosavuta kumva. Tiyeni tione aliyense wa iwo:

• * - amasankha zinthu zonse tsamba, kuphatikizapo mutu, thupi, etc.
• tsa / div / sidebar / ... - amasankha zinthu zonse zokhudza chidutswa cha anakonzeratu (ie kuti p.div, sidebar, etc ...);
• .myClass / p.myClass - amasankha zinthu ndi mwachindunji dzina kalasi;
• # MyID / tsa # myID -. Amasankha aliyense item wina ndi ID anapatsidwa.

Pano pali chitsanzo. Tiyeni tinene tiyenera kusankha zinthu zonse patsamba ndi kulowa ndime kalasi adzakhala motere: (. Ndime) $. Ngati ndi kotheka kokha tsa mfundo za kalasi, ndiye kulemba: $ (p.par).

am'patse selectors

Mukhoza kugwiritsa ntchito jQuery waukulu-selector, ngati tiyenera kusankha item wachokera ku kalasi iliyonse ndi ID kapena kusankha zinthu zonse pa tsamba. Komabe, pali milandu pamene chinthu alibe kalasi kapena ID. Ndi zimenezi ndipo pali masankhidwe ndi lingaliro. Iwo amakulolani kupanga kusankha zina khalidwe la HTML-zinthu, monga href kapena SRC. Chikhalidwe ichi zinalembedwa m'mabokosi lalikulu [].

Chitsanzo losavuta: $ ([SRC]) - amasankha zinthu zonse ndi SRC lingaliro. N'zotheka kuti achepetse nyemba ndi malangizo ena chikhumbo mtengo: $ ([SRC = 'HTTP: // malo / Nkhani / 132222 / phindu']).

Mukhoza kugwiritsa ntchito zina selectors jQuery ngati mukufuna kuti achepetse munda wa kusankha. Mwachitsanzo, $ (p [mtundu = buluu] [kukula = 12]) - amasankhidwa okhawo zinthu tsa, omwe mtundu buluu ndi kukula 12.

Selectors okhutira

Zikatero, ngati inu simungakhoze kusankha zinthu zochokera makhalidwe kapena selectors zofunika, muyenera amanena kuti amanena. Okwana pali 4 selector wa mtundu uwu:

• : Muli - amasankha zinthu munali mwachindunji lemba;
• : Kodi - amasankha zinthu zimene muli zinthu zina khalidwe la mzere;
• : Kholo - amasankha zinthu zimene zili ina;
• : Chopanda - amasankha zinthu zimene mulibe wina aliyense.

Pano pali chitsanzo. Kusankha zinthu zonse div, ndi malemba wa Hello, muyenera kulemba $ (div: lili ( 'Moni')).

Selectors wolowezana

Pali njira ina kusankha zinthu zina jQuery, ndicho - malinga ndi utsogoleri wolowezana awo (ndiko kuti, chiŵerengero cha mzake pa HTML tsamba). Ambiri a iwo, kotero tilalikira awiri otchuka kwambiri, "mwana" ndi "Mbeu".

Mbali yoyamba zinthu amasankhidwa, ndiwo ana mwachindunji (ana) wa chinthu anapatsidwa (makolo). Mwachitsanzo, kusankha zinthu za mndandanda m'kalasi kuwunika kuli mndandanda mwana NAV pofika, ndiye muyenera kulemba: $ (up # NAV pofika> li.light).

Nkhani yachiwiri - kwambiri ambiri. Pali akhoza anasankha ndi ana zotsalira za mchitidwe wa. Mwachitsanzo, kusankha limasonyeza mkati mndandanda NAV pofika mankhwala: $ (up # NAV pofika a).

Choncho, jQuery zinthu akhoza anasankha m'njira zosiyanasiyana pogwiritsa ntchito magawo monga kalasi, ID, makhalidwe zili kapena utsogoleri wolowezana wa zinthu HTML-chikalata.