杩欎竴鐐圭殑闂锛屽洜涓烘秹鍙婂埌鐨勭煡璇嗙偣姣旇緝澶氾紝鍒濆鐨勬椂鍊欐€绘槸涓嶆竻妤氥€傛枃妗ｇ湅澶氫簡澶存檿銆備粖澶╁弽澶嶉槄璇昏杽鍏堢敓鐨勬枃浠讹紝鍊熸鏈轰細鍐欎笅鑷繁鐨勪竴浜涙兂娉曪紝宸╁浐璁板繂锛屽姞娣辩悊瑙ｃ€傪煃撳弬鑰冭祫鏂欙細鍓嶇楂樼骇鍩虹锛堜竷锛夛細鍏ㄩ潰瑙ｈthis鍒氬紑濮嬪涔犵殑鏃跺€欙紝鏈変竴鍙ヨ瘽娣卞緱鎴戝績锛氳皝鍙皝锛宼his灏辨寚鍚戣皝銆傝繖閲岀殑鈥渋t鈥濇寚鐨勬槸鍑芥暟锛岃皝璋冪敤杩欎釜鍑芥暟锛岃繖涓嚱鏁颁腑鐨則his灏辨寚鍚戣皝銆傝繖绉嶈娉曚篃瀵癸紝浣嗕笉瀹屽叏姝ｇ‘銆傚畠鍙槸鎬荤粨浜唗his鎸囧悜鐨勪竴绉嶆儏鍐点€傚湪鍚庢潵鐨勫紑鍙戣繃绋嬩腑锛屾垜瓒婃潵瓒婃剰璇嗗埌杩欑璇存硶鐨勭己闄枫€傝繖涓偣鏄粈涔堟椂鍊欑‘瀹氱殑锛熼鍏堢涓€涓棶棰橈紝杩欎釜鐐规槸浠€涔堟椂鍊欑‘瀹氱殑锛熻鎴戜滑鍥為【涓€涓嬫墽琛屼笂涓嬫枃銆傚湪鎵ц涓婁笅鏂囩殑鍒涘缓闃舵锛屽仛浜嗕笁浠朵簨锛氬垱寤哄彉閲忓璞★紝寤虹珛浣滅敤鍩熼摼锛岀‘瀹歵his鐨勬寚鍚戰焼椼€傛棦鐒秚his鐨勯噸鐐规槸鍦ㄦ墽琛屼笂涓嬫枃鐨勫垱寤洪樁娈靛氨纭畾浜嗭紝閭ｄ箞鎵ц涓婁笅鏂囨槸浠€涔堟椂鍊欏垱寤虹殑鍛紵鎵ц涓婁笅鏂囧彲浠ョ畝鍗曠悊瑙ｄ负褰撳墠浠ｇ爜鐨勬墽琛岀幆澧冿紝浼氬垱寤轰竴涓綔鐢ㄥ煙锛涙墽琛岀幆澧冨垎涓哄叏灞€鐜銆佸嚱鏁扮幆澧冨拰eval锛堝ぇ閮ㄥ垎鎯呭喌涓嬪彲浠ュ拷鐣ワ級锛涘叏灞€鎵ц涓婁笅鏂囦綅浜庤剼鏈唬鐮佺殑寮€澶淬€傚畠琚垱寤猴紱鍑芥暟鐨勬墽琛屼笂涓嬫枃鏄湪璋冪敤鍑芥暟鏃跺垱寤虹殑锛涘綋鎴戠煡閬撯€滅‘瀹氳繖涓€鐐?>鎵ц涓婁笅鏂囧垱寤洪樁娈?>鍑芥暟琚皟鐢ㄢ€濈殑闆嗗悎鏃讹紝鎴戣瘯鐫€闂嚜宸憋紝鈥滆皟鐢ㄥ嚱鏁板彂鐢熶簡浠€涔堬紵鈥濅粈涔堬紵鈥濇垜娌℃湁椹笂鍥炵瓟锛岀劧鍚庢垜鎰忚瘑鍒版垜杩橀渶瑕佹繁鍏ョ悊瑙ｅ拰璁板繂銆傜粨璁猴細杩欎釜鐐规槸鍦ㄦ墽琛屼笂涓嬫枃鍒涘缓闃舵纭畾鐨勨潳浣犱篃鍙互鐞嗚В涓衡€滆繖涓偣鏄湪浠€涔堟椂鍊欑‘瀹氱殑鈥漷hefunctioniscalled鈥濓紝浣嗘槸涓€瀹氳璁颁綇锛岃皟鐢ㄥ嚱鏁颁細鍒涘缓鎵ц涓婁笅鏂囷紝鐒跺悗纭畾this鐐广€倀his鎸囧悜璋侊紵鍥犱负this鐐规槸鍦ㄨ皟鐢ㄥ嚱鏁版椂纭畾鐨勶紝this鐐逛竴涓嚱鏁扮殑瀹氫箟鍙互寰堢伒娲伙紝涓嬮潰鐨勪緥瀛愶紝鍚屼竴涓嚱鏁帮紝鐢变簬璋冪敤鏂瑰紡涓嶅悓锛宼his鎸囧悜涓嶅悓鐨勫璞ara=10;varobj={a:20}functionfn(){console.log(this.a);}fn();//10fn.call(obj);//20銆佺敤call鏀瑰彉this鍙﹀锛屽湪鍑芥暟鎵ц杩囩▼涓紝this涓€鏃︾‘瀹氾紝灏变笉鑳藉啀鏀瑰彉銆倂ara=10;varobj={a:20}functionfn(){this=obj;//杩欏彞璇濆皾璇曚慨鏀箃his锛岃繍琛屽悗浼氭姤閿檆onsole.log(this.a);}fn();,鍏ㄥ眬瀵硅薄涓殑this鍏ㄥ眬瀵硅薄鐨則his鏄竴涓壒娈婄殑瀛樺湪锛屾寚鍚戣嚜韬紝涔熷氨鏄寚鍚戝叏灞€鐜銆?/閫氳繃this缁戝畾鍒板叏灞€瀵硅薄this.a2=20;//閫氳繃澹版槑缁戝畾鍒板彉閲忓璞★紝浣嗘槸鍦ㄥ叏灞€鐜涓嬶紝鍙橀噺瀵硅薄鏈韩灏辨槸vara1=10;//鍙湁璧嬪€兼搷浣滐紝identifier浼氳闅愬紡缁戝畾鍒板叏灞€瀵硅薄a3=30;//杈撳嚭鐨勭粨鏋滈兘浼氱鍚坧re-consoleconsole.log(a1);console.log(a2);console.log(a3);浜屻€佸嚱鏁颁腑鐨則his鍦ㄥ嚱鏁颁笂涓嬫枃涓紝this鐢辫皟鐢ㄨ€呮彁渚涳紝鎸囬拡鐢卞嚱鏁扮殑璋冪敤鏂瑰紡鍐冲畾銆傚鏋滆皟鐢ㄨ€呭嚱鏁板睘浜庝竴涓璞★紝閭ｄ箞褰撳嚱鏁拌璋冪敤鏃讹紝鍐呴儴鐨則his鎸囧悜璇ュ璞°€傚鏋滃嚱鏁拌鐙珛璋冪敤锛岄偅涔堝嚱鏁板唴閮ㄧ殑this鎸囧悜undefined銆傚湪闈炰弗鏍兼ā寮忎笅锛屽綋this鎸囧悜undefined鏃讹紝浼氳嚜鍔ㄦ寚鍚戝叏灞€瀵硅薄銆傝鍑嗙‘鍒ゆ柇this鐨勬寚鍚戯紝鎵惧埌鍑芥暟鐨勮皟鐢ㄨ€咃紝鍖哄垎鏄惁鏄嫭绔嬭皟鐢ㄥ緢閲嶈銆?/涓轰簡鑳藉鍑嗙‘鍒ゆ柇锛屾垜浠湪鍑芥暟鍐呴儴浣跨敤涓ユ牸妯″紡锛屽洜涓洪潪涓ユ牸妯″紡浼氳嚜鍔ㄦ寚鍚戝叏灞€瀵硅薄functionfn(){'usestrict';console.log(this);}fn();//fn涓篊aller锛岀嫭绔嬭皟鐢╳indow.fn()锛?/fn鏄皟鐢ㄨ€咃紝灞炰簬window鍙︿竴涓洶闅剧殑渚嬪瓙锛歷ara=20;varfoo={a:10,getA:function(){returnthis.a;}}console.log(foo.getA());//10vartest=foo.getA;console.log(test());//20test()浣滀负璋冪敤鑰咃紝铏界劧鍜宖oo.getA()涓嶄竴鏍凤紝浣嗘槸鏄嫭绔嬭皟鐢ㄧ殑锛屾墍浠his鎸囧悜undefined銆傚湪闈炰弗鏍兼ā寮忎笅锛屽畠浼氳嚜鍔ㄨ浆鍚戝叏灞€绐楀彛銆倂ara=20;functiongetA(){returnthis.a;}varfoo={a:10,getA:getA}console.log(foo.getA());//10functionfoo(){console.log(this.a)}functionactive(fn){fn();//鐪熸鐨勮皟鐢ㄨ€咃紝鐢ㄤ簬鐙珛璋冪敤}vara=20;varobj={a:10,getA:foo}active(obj.getA);,浣跨敤call,apply鎸囧畾鐩爣thisJavaScript鍐呴儴鎻愪緵浜嗕竴绉嶆満鍒讹紝鍙互璁╂垜浠嚜宸辨墜鍔ㄨ缃畉his鐨勬柟鍚戯紝鍗砪all鍜宎pply銆傗潳褰撲綘鐞嗚Вcall鍜宎pply鐨勬椂鍊欙紝璁板緱鎶婂畠鐞嗚В涓鸿皟鐢ㄥ嚱鏁板苟鎸囧畾this涓虹洰鏍囧璞★紝鑰屼笉鏄瀵硅薄鍘昏皟鐢ㄤ笉灞炰簬鑷繁鐨勬柟娉曘€俧unctionfn(num1,num2){console.log(this.a+num1+num2);}varobj={a:20}fn.call(obj,100,10);//130fn.apply(obj,[20,10]);//50call鍜宎pplay鍚庨潰鐨勫弬鏁伴兘鏄紶閫掔粰瑕佹墽琛岀殑鍑芥暟鐨勫弬鏁般€傝皟鐢ㄤ竴涓竴涓紶閫掞紝apply浠ユ暟缁勭殑褰㈠紡浼犻€掋€傝繖鏄粬浠敮涓€鐨勫尯鍒€?.鏋勯€犲嚱鏁颁腑鐨則hisfunctionPerson(name,age){//杩欓噷this鎸囧悜璋侊紵this.name=鍚嶇О锛涜繖涓€傚勾榫?骞撮緞锛泒Person.prototype.getName=function(){//杩欓噷this鎸囧悜璋侊紵returnthis.name;}//涓婇潰鐨勪袱涓猼his鏄惁鐩稿悓锛屾槸鍚︽寚鍚戝師鍨嬪璞★紵varp1=newPerson('灏煎厠',20);console.log(p1.getName());//褰撯€淣ick鈥濋€氳繃new鎿嶄綔绗﹁皟鐢ㄦ瀯閫犲嚱鏁版椂锛屼細缁忓巻4涓樁娈碉細鍒涘缓涓€涓柊瀵硅薄锛涘皢鏋勯€犲嚱鏁扮殑this鎸囧悜杩欎釜鏂板璞★紙鐙珛璋冪敤鍘熸瀯閫犲嚱鏁帮紝鍐呴儴this鎸囧悜undefined锛夛紱鎵ц鏋勯€犲嚱鏁扮殑浠ｇ爜锛屼负杩欎釜瀵硅薄娣诲姞灞炴€с€佹柟娉曠瓑锛涜繑鍥炰竴涓柊瀵硅薄锛涘綋new鎿嶄綔绗﹁皟鐢ㄦ瀯閫犲嚱鏁版椂锛宼his瀹為檯鎸囧悜鏂板垱寤虹殑瀵硅薄锛屾渶缁堟柊瀵硅薄杩斿洖骞惰example瀵硅薄鎺ュ彈銆傛墍浠ユ垜浠彲浠ヨ鏋勯€犲嚱鏁扮殑this鎸囧悜浜嗘柊鐨勫疄渚嬪璞°€?.绠ご鍑芥暟涓繖涓紙鐗规畩锛塎DN瀹樻柟瑙ｉ噴锛氱澶村嚱鏁扮殑寮曞叆鏈変袱涓綔鐢細鏇寸煭鐨勫嚱鏁板拰涓嶇粦瀹歵his銆傜澶村嚱鏁颁笉鍒涘缓鑷繁鐨則his锛屽畠鍙槸浠庡叾浣滅敤鍩熼摼鐨勪笂涓€灞傜户鎵縯his銆傜澶村嚱鏁拌〃杈惧紡鐨勮娉曟瘮鍑芥暟琛ㄨ揪寮忔洿绠€娲侊紝骞朵笖娌℃湁鑷繁鐨則his銆乤rguments銆乻uper鎴杗ew.target銆傜澶村嚱鏁拌〃杈惧紡鏇撮€傜敤浜庨渶瑕佸尶鍚嶅嚱鏁扮殑鍦版柟锛屽畠涓嶈兘鐢ㄤ綔鏋勯€犲嚱鏁般€傜敱浜庣澶村嚱鏁版病鏈夎嚜宸辩殑this鎸囬拡锛岄€氳繃call()銆乤pply()鎴朾ind()鏂规硶璋冪敤鍑芥暟鏃讹紝鍙兘浼犻€掑弬鏁帮紝涓嶈兘缁戝畾this锛屽畠浠殑绗竴涓弬鏁颁細琚拷鐣?鍙傝€冭祫鏂欙細绠ご鍑芥暟-JavaScript|MDN閲嶅啓call/apply/bind鏂规硶鍖哄埆call鍜宐ind鍙互鎺ュ彈澶氫釜鍙傛暟锛岀涓€涓弬鏁版槸this鎸囧悜鐨勭洰鏍囧璞★紱apply鍙兘鎺ュ彈涓や釜鍙傛暟锛岀涓€涓弬鏁癟his鎸囧悜鐩爣瀵硅薄锛岀浜屼釜鍙傛暟鏄竴涓暟缁勶紝瀛樻斁鍑芥暟浣跨敤鐨勫弬鏁帮紱bind杩斿洖涓€涓嚱鏁帮紝call鍜宎pply绔嬪嵆鎵ц锛沚ind瀹炵幇浜嗗嚱鏁版煰閲屽寲锛屽彲浠ヤ袱娆″悜鐩爣鍑芥暟浼犻€掑弬鏁帮紱璋冪敤//璋冪敤Function.prototype.myCall=function(context,...args){if(context==undefined||context==null){context=window;}console.log(context)context.fn=this;console.log('this',this)//myCall鐨勮皟鐢ㄨ€呮槸涓€涓嚱鏁帮紱constresult=context.fn(...args);console.log(context)//瀵硅薄锛屽寘鎷繖涓偣锛屽拰鎵ц鍑芥暟锛涘垹闄ontext.fn锛?/鍙兘鍥犱负寮曠敤绫诲瀷鏁版嵁鏀瑰彉浜嗗師鍙橀噺锛屽垹闄onsole.log(result)//鍑芥暟鎵ц杩斿洖returnresult;}constobj1={basicNum:1,sum:function(a,b){return(a+b+this.basicNum);}}constobj2={basicNum:10,}console.log(obj1.sum(2,3));console.log(obj1.sum.call(obj2,2,3));console.log(obj1.sum.myCall(obj2,2,3));apply//搴旂敤Function.prototype.myApply=function(context,args){if(context==undefined||context==null){context=window;}context.fn=杩欎釜锛沜onstresult=context.fn(...args);鍒犻櫎context.fn锛涜繑鍥炵粨鏋渳constobj1={basicNum:1,sum:function(a,b){return(a+b+this.basicNum);}}constobj2={basicNum:10,}console.log(obj1.sum(2,3));console.log(obj1.sum.apply(obj2,[2,3]));console.log(obj1.sum.myBind(obj2,[2,3]));bind//缁戝畾Function.prototype.myBind=function(context,...initArgs){if(context==undefined||context==绌猴級涓婁笅鏂?绐楀彛锛沜onst_this=杩欎釜锛涜繑鍥炲嚱鏁?...args){context.fn=_this;constresult=context.fn(...initArgs,...args);杩斿洖缁撴灉锛泒}constobj1={basicNum:1,sum:function(a,b){return(a+b+this.basicNum);}}constobj2={basicNum:10,}console.log(obj1.sum(2,3));console.log(obj1.sum.bind(obj2,2,3)());console.log(obj1.sum.myBind(obj2,2)(3));琛ュ厖鐗规畩鎯呭喌锛岃鑰冭檻constobj={birth:1990,getAge:function(year){letfn=y=>{console.log(this);//objreturny-this.birth;}console.log(fn.prototype);//undefinedreturnfn.call({birth:2000},year);}};console.log(obj.getAge(2020));//20杩樻槸30锛熸寜鐓у墠闈㈢殑璇存硶锛宑all鏀瑰彉浜唗his鐨勬柟鍚戯紝閭ｄ箞绛旀鏄?020-2000锛屽簲璇ユ槸30锛涗絾鏄紝fn鏄竴涓澶村嚱鏁帮紝鏈韩娌℃湁this瀵硅薄锛屼篃娌℃湁鍘熷瀷瀵硅薄锛岃皟鐢ㄤ笉鑳芥敼鍙榯his鐨勬柟鍚戯紱
