TA貢獻(xiàn)1827條經(jīng)驗 獲得超8個贊
抓住兩個關(guān)鍵點很重要：js中函數(shù)是引用類型；函數(shù)一般執(zhí)行方式:函數(shù)名+()；下面的例子幫你理解引用類型vara=function(x,y){console.log(x+y);};varb=a;a(1,2);b(1,2);//b,a指向同一個函數(shù)對象//b重新賦值b=function(x,y){console.log(x-y);}a(1,2);b(1,2);如果還是不理解，參考下這篇文章：javascript中的引用類型接下來說明下函數(shù)的幾種定義方式：函數(shù)聲明alert(sum(1,2));functionsum(x,y){returnx+y;}函數(shù)表達(dá)式//這段代碼會報錯alert(sum(1,2));varsum=function(x,y){returnx+y;}在寫遞歸的時候可以這樣寫//如果直接用sum(x-1)+sum(x-2),如果sum被改名，或者重新賦值，產(chǎn)生bugvarsum=functionfSum(x){if(x<=2)return1;elsereturnfSum(x-1)+fSum(x-2);};alert(sum(5));匿名函數(shù)(function(x,y){alert(x+y);})(1,2);
TA貢獻(xiàn)1835條經(jīng)驗 獲得超7個贊
普通函數(shù):functionsquare(x){returnx*x;}console.log(square(3));用var聲明的匿名函數(shù):varsquare=(function(x){returnx*x;});或者varsquare=function(x){returnx*x;};console.log(square(3));匿名函數(shù)(其中(3)表示傳入?yún)?shù)3并執(zhí)行此匿名函數(shù)):(function(x){returnx*x;})(3);或者(function(x){returnx*x;}(3));
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