對(duì)象應(yīng)用
聲明和實(shí)例化
1) 對(duì)象使用關(guān)鍵字new后跟實(shí)例化的類的名字創(chuàng)建的
1 var oObject = new Object();
2 var oString = new String();
2) 如果構(gòu)造函數(shù)無(wú)參數(shù)，括號(hào)則可以省略
var oObject = new Object;但一般推薦使用
對(duì)象的廢除
1、JS有無(wú)用存儲(chǔ)單元收集程序，可以自動(dòng)的銷毀無(wú)用的對(duì)象
2、把所有對(duì)象的值設(shè)為null，可以強(qiáng)制性廢除對(duì)象
1 var oObject = new Object();
2 oObject = null;
Array類
1、創(chuàng)建Array類
1 var aValues1 = new Array();
2 var aValues2 = new Array(20);
3 var aValues3 = new Array("red","black","blue");
4 var aValues4 = ["a","b","C"];
2、屬性
length 得到數(shù)組的長(zhǎng)度
1 var aValues = new Array(20);
2 alert(aValues.length);//output 20
3、方法
1)toString()&valuesOf() 輸出數(shù)字值
1 var aValues = new Array("red","blue","yellow");
2 alert(aValues.toString());//output red,blue,yellow
2)join() 用指定字符輸出數(shù)字值
1 var aValues = new Array("A","B");
2 alert(aValues.join('-'));//output A-B
3)split() 將字符串轉(zhuǎn)換為數(shù)組
1 var sColor = "red,gree,blue";
2 var sArray = sColor.split(",");
3 alert(aArray.toString());//output red,gree,blue
4)concat() 連字符串連接
1 var aValues1 = ["A","B","C"];
2 var aValues2 = sValues1.concat("D","E");
3 alert(aValues1.toString());//output A,B,C
4 alert(aValues2.toString());//output A,B,C,D,E
5)slice() 返回一個(gè)數(shù)組,該數(shù)組是原數(shù)組的子集,始于<始>,終于<終>。如果不給出<終>，則子集一直取到原數(shù)組的結(jié)尾。
1 var aValues = ["a","b","c","d"];
2 alert(aValues.slice(1));//output b,c,d
3 alert(aValues.slice(1,2));//output b
6)push() 用于在數(shù)組的結(jié)尾添加一個(gè)或多個(gè)項(xiàng)
1 var stack = new Array();
2 stack.push("A");
3 stack.push("B");
4 stack.push("C","D");
5 alert(stack.toString());//output A,B,C,D
7)pop() 用于刪除最后一個(gè)數(shù)組項(xiàng)
1 var stack = new Array("a","b","c");
2 alert(stack.toString());
3 stack.pop();
4 alert(stack.toString());
8)shift() 刪除數(shù)組中的第一個(gè)項(xiàng)
1 var aitem = ["red","black","blus"];
2 alert(aitem.toString());//output red,black,blue
3 alert.shift();
4 alert(aitem.toString());//output black,blue
9)unshift() 把一個(gè)項(xiàng)放入到數(shù)組的第一個(gè)位置，然后把其余的項(xiàng)向后推一個(gè)位置
1 var vltem = ["A","B","C","D"];
2 alert(vltem.toString());//output A,B,C,D
3 vltem.unshift("E");
4 alert(vltem.toString());//out put E,A,B,C,D
10)reverse() 顛倒數(shù)組順序
1 var vltem = ["red","black","blue"];
2 vltem.reverse();
3 alert(vltem.toString());//out put blue,black,red
11)sort() 對(duì)數(shù)組進(jìn)行升序排序
1 var vltem = ["red","black","blue"];
2 vltem.sort();
3 alert(vltem.toString());//output black,blue,red
12)splice() 用于插入、刪除或替換數(shù)組的元素
oObject.splice(index,howmany,element1,......,elementX)
參數(shù)index 必需，規(guī)定從何處添加或刪除元素。該參數(shù)是開始插入和(或)刪除的數(shù)組元素的下標(biāo)，必須是數(shù)字
參數(shù)howmany 必需，規(guī)定應(yīng)該刪除多少元素。必須是數(shù)字，但可以是"0".如果為規(guī)定此參數(shù)，則刪除從index開始到原數(shù)組結(jié)尾的所有元素
參數(shù)element1 可選，規(guī)定要添加到數(shù)組的新元素。從index所指的下標(biāo)處開始插入
參數(shù)elementx 可選，可向數(shù)組添加若干元素。
1 var stack = new Array();
2 stack.push("a");
3 stack.push("b");
4 stack.push("c");
5 stack.push("d");
6 stack.push("e");
7 alert(stack.toString());//output a,b,c,d,e
8 alert(stack.splice(2,3,"q"));
9 alert(stack.toString());//putput a,b,q