js數(shù)據(jù)類型以及數(shù)組字符串常??法JS判斷數(shù)據(jù)類型例?：vara="iamstring.";varb=222;varc=[1,2,3];vard=newDate();vare=function(){alert(111);};varf=function(){="22";};1、最常見判斷?法：typeof可以判斷基本數(shù)據(jù)類型，對于引?數(shù)據(jù)類型就要?別的alert(typeofa)------------>stringalert(typeofb)------------>numberalert(typeofc)------------>objectalert(typeofd)------------>objectalert(typeofe)------------>functionalert(typeoff)------------>function2、判斷已知對象類型?法：instanceofalert(cinstanceofArray)--------------->truealert(dinstanceofDate)alert(finstanceofFunction)------------>truealert(finstanceoffunction)------------>false3、根據(jù)對象的constructor判斷：constructoralert(c.constructor===Array)---------->truealert(d.constructor===Date)----------->truealert(e.constructor===Function)------->true注意：constructor在類繼承時(shí)會出錯(cuò)4、?敵通??法jQuery.type()jQuery.type(undefined)==="undefined"jQuery.type()==="undefined"jQuery.type(window.notDefined)==="undefined"jQuery.type(null)==="null"jQuery.type(true)==="boolean"jQuery.type(3)==="number"jQuery.type("test")==="string"jQuery.type(function(){})==="function"jQuery.type([])==="array"jQuery.type(newDate())==="date"jQuery.type(newError())==="error"http://asofjQuery1.9jQuery.type(/test/)==="regexp"JQuery判斷jQuery.isArray():是否為數(shù)組，返回值為?個(gè)布爾jQuery.isFunction():是否為函數(shù)jQuery.isPlainObject():是否為使?{}或newObject?成對象jQuery.isNumeric():是否為數(shù)字Js常?字符串處理?法js?帶函數(shù)concat(將兩個(gè)或者多個(gè)字符?本組合起來，返回?個(gè)新的字符串)“hello”vara=“,world”varb=“snow”vard=(b,d);varc=a.concat(c)//“hello,worldsnow”Console.logindexOf(返回字符串中?個(gè)?串第?次出現(xiàn)的索引值，從左到右，如果沒值則返回-1)varindex1=a.indexOf(‘l’);//index1=2;varindex2=a.indexOf(“l(fā)”,3);//index2=3chartAt(返回指定位置的字符)varget_char=a.chartAt(0);//get_char=“h”lastIndexOf(返回字符串中?個(gè)?串最后?處出現(xiàn)的索引，從右向左搜索，如果沒有匹配，返回-1)varindex1=a.lastindexOf(‘l’);//index1=3;varindex2=a.lastindexOf(“l(fā)”,3);//index2=2match(檢查?個(gè)字符串匹配?個(gè)正則表達(dá)式內(nèi)容，如果沒有則返回null)varre=newRegExp(/^\w+$/);

varis_Ma=a.match(re);//is_Ma=“hello”varis_Ma2=b.match(re);//is_Ma2=nullsubstring(返回字符串的?個(gè)?串，傳?參數(shù)是起始位置和結(jié)束位置)varsub_string1=a.substring(1);//sub_string1="ello"varsub_string2=a.substring(1,4);//sub_string2="ell"substr(返回字符串的?個(gè)?串，傳?參數(shù)是起始位置和長度)varsub_string1=a.substr(1);//sub_string1="ello"varsub_string2=a.substr(1,4);//sub_string2="ello"replace(?來查找匹配?個(gè)正則表達(dá)式字符串，然后使?新字符代替匹配的字符串)varresult1=a.replace(re,"Hello");//result1="Hello"varresult2=b.replace(re,"Hello");//result2=",world"search(執(zhí)??個(gè)正則表達(dá)式匹配查找，如果查找成功，返回字符串匹配的索引，否則返回-1)varindex1=a.search(re);//index1=0varindex2=b.search(re);//index2=-1slice(提取字符串的?個(gè)?串，返回?個(gè)新的字符串，傳?參數(shù)是起始位置和結(jié)束位置，同substring)split(通過將字符串劃分成?串，將?個(gè)字符串做出字符串?dāng)?shù)組)vararr1=a.split("");//arr1=[h,e,l,l,o]length()varlen=a.length();//len=5toLowerCase()varlower_string=a.toLowerCase();//lower_string="hello"toUpperCase()varupper_string=a.toUpperCase();//upper_string="HELLO"js常?數(shù)組處理?法(藍(lán)?為es5新增數(shù)組?法)join()->將數(shù)組元素組起?個(gè)字符串，以??定義的符號分割，省略的話則以逗號分割，該?法只接收?個(gè)參數(shù)：分隔符vararr=[1,2,3];console.log(arr.join());//1,2,3Console.log(arr.join(“-”));//1-2-3push()和pop()push():可以接收任意數(shù)量的參數(shù)，逐個(gè)添加到數(shù)組末尾，并返回修改后的數(shù)組長度；pop():數(shù)組末尾移除最后?項(xiàng)，減少數(shù)組的length值，返回移除的項(xiàng)vararr=["Lily","lucy","Tom"];varcount=arr.push("Jack","Sean");console.log(count);//5console.log(arr);//["Lily","lucy","Tom","Jack","Sean"]varitem=arr.pop();console.log(item);//Seanconsole.log(arr);//["Lily","lucy","Tom","Jack"]shift()和unshift()shift():刪除原數(shù)組第?項(xiàng)，并返回刪除的元素；如果為空則返回undefined;unshift():將參數(shù)添加到原數(shù)組開頭，并返回?cái)?shù)組的長度vararr=["Lily","lucy","Tom"];varcount=arr.unshift("Jack","Sean");console.log(count);//5console.log(arr);//["Jack","Sean","Lily","lucy","Tom"]varitem=arr.shift();console.log(item);//Jackconsole.log(arr);//["Sean","Lily","lucy","Tom"]sort()->按升序排列數(shù)組項(xiàng)在排序的時(shí)候，sort()?法會先把數(shù)組的每?項(xiàng)轉(zhuǎn)化為字符串再?較(toString())，因此會出現(xiàn)數(shù)字不是按照升序的?式排列這時(shí)候就需要??寫?個(gè)?法來調(diào)?functioncompare(value1,value2){if(value1<value2){return-1;}elseif(value1>value2){

return1;}else{return0;}}arr2=[13,24,51,3];console.log(arr2.sort());//[13,24,3,51]直接調(diào)?排序的話console.log(arr2.sort(compare));//[3,13,24,51]reverse()->反轉(zhuǎn)數(shù)組項(xiàng)順序vararr=[13,24,51,3];console.log(arr.reverse());//[3,51,24,13]console.log(arr);//[3,51,24,13](原數(shù)組改變)concat()->將參數(shù)添加到數(shù)組中，然后返回?個(gè)新構(gòu)建的數(shù)組，原數(shù)組未改變vararr=[1,3,5,7];vararrCopy=arr.concat(9,[11,13]);console.log(arrCopy);//[1,3,5,7,9,11,13]console.log(arr);//[1,3,5,7](原數(shù)組未被修改)slice()->返回從原數(shù)組指定開始下標(biāo)和結(jié)束下標(biāo)之間的新數(shù)組，有兩個(gè)參數(shù)，如果參數(shù)出現(xiàn)負(fù)值，則為負(fù)數(shù)加上數(shù)組的長度的值vararr=[1,3,5,7,9,11];vararrCopy=arr.slice(1);vararrCopy2=arr.slice(1,4);vararrCopy3=arr.slice(1,-2);vararrCopy4=arr.slice(-4,-1);console.log(arr);//[1,3,5,7,9,11](原數(shù)組沒變)console.log(arrCopy);//[3,5,7,9,11]console.log(arrCopy2);//[3,5,7]console.log(arrCopy3);//[3,5,7]console.log(arrCopy4);//[5,7,9]splice()->可以實(shí)現(xiàn)刪除，插?和替換，最終返回刪除的選項(xiàng)數(shù)組刪除：可以刪除任意數(shù)量的項(xiàng)，只需指定2個(gè)參數(shù)：要刪除的第?項(xiàng)的位置和要刪除的項(xiàng)數(shù)。例如，splice(0,2)會刪除數(shù)組中的前兩項(xiàng)。插?：可以向指定位置插?任意數(shù)量的項(xiàng)，只需提供3個(gè)參數(shù)：起始位置、0（要刪除的項(xiàng)數(shù)）和要插?的項(xiàng)。例如，splice(2,0,4,6)會從當(dāng)前數(shù)組的位置2開始插?4和6。替換：可以向指定位置插?任意數(shù)量的項(xiàng)，且同時(shí)刪除任意數(shù)量的項(xiàng)，只需指定3個(gè)參數(shù)：起始位置、要刪除的項(xiàng)數(shù)和要插?的任意數(shù)量的項(xiàng)。插?的項(xiàng)數(shù)不必與刪除的項(xiàng)數(shù)相等。例如，splice(2,1,4,6)會刪除當(dāng)前數(shù)組位置2的項(xiàng)，然后再從位置2開始插?4和6。vararr=[1,3,5,7,9,11];vararrRemoved=arr.splice(0,2);console.log(arr);//[5,7,9,11]console.log(arrRemoved);//[1,3]vararrRemoved2=arr.splice(2,0,4,6);console.log(arr);//[5,7,4,6,9,11]console.log(arrRemoved2);//[]vararrRemoved3=arr.splice(1,1,2,4);console.log(arr);//[5,2,4,4,6,9,11]console.log(arrRemoved3);//[7]indexOf()和lastIndexOf()返回要查找的項(xiàng)的位置索引，沒找到返回-1indexOf():接收兩個(gè)參數(shù)，要查找的項(xiàng)和表?查找起點(diǎn)位置的索引（可選），從數(shù)組開頭往后查找lastIndexOf():同上，只是從數(shù)組末尾開始向前查找vararr=[1,3,5,7,7,5,3,1];console.log(arr.indexOf(5));//2console.log(arr.lastIndexOf(5));//5console.log(arr.indexOf(5,2));//2console.log(arr.lastIndexOf(5,4));//2console.log(arr.indexOf("5"));//-1forEach()->對數(shù)組進(jìn)?遍歷循環(huán)，對數(shù)組中的每?項(xiàng)運(yùn)?給定函數(shù)，沒有返回值；參數(shù)分別為：遍歷的數(shù)組內(nèi)容；對應(yīng)的數(shù)組索引；數(shù)組本?vararr=[1,2,3,4,5];arr.forEach(function(x,index,a){console.log(x+'|'+index+'|'+(a===arr));});//輸出為：//1|0|true//2|1|true//3|2|true//4|3|true//5|4|truemap()->映射，對數(shù)組中每?項(xiàng)運(yùn)?給定的函數(shù)，返回每次函數(shù)調(diào)?的結(jié)果組成的數(shù)組vararr=[1,2,3,4,5];vararr2=arr.map(function(item){returnitem*item;});console.log(arr2);//[1,4,9,16,25]filter()->過濾功能，數(shù)組中每?項(xiàng)運(yùn)?給定的函數(shù)，返回滿?條件組成的數(shù)組vararr=[1,2,3,4,5,6,7,8,9,10];vararr2=arr.filter(function(x,index){returnindex%3===0||x>=8;});console.log(arr2);//[1,4,7,8,9,10]every()->判斷數(shù)組中每?項(xiàng)是否滿?條件，只有所有項(xiàng)都滿?才會返回truevararr=[1,2,3,4,5];

vararr2=arr.every(function(x){returnx<10;});console.log(arr2);//truevararr3=arr.every(functio