How to declare objects in js and some usage examples of arrays_Basic knowledge

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<script> <br>//Define a printing function<br>var $=function(str) { <br>document.write(str); <br>document.write("<br/>"); <br>} <br>//Define the print array function<br>var _=function(arr ){ <br>for(var tmp in arr) <br>{ <br>$(arr[tmp]); <br>} <br>} <br>//Define a student object <br>var stu= new Object(); <br><br>//Declare properties and behaviors <br>stu.id=16; <br>stu.name='Lamp Coin'; <br>stu.age=function(){ <br>return this.id; <br>} <br><br>//Print student information <br>$(stu.id); <br>$(stu.name); <br>$(stu. age()); //Add brackets when calling <br><br>stu.sex='female'; //Add new attributes<br>$(stu.sex); //Print the newly added attributes<br><br>//Option 2: <br>function Student(id,name) <br>{ <br>this.id=id; <br>this.name=name; <br>this.getAge=function( ){ <br>return this.id; <br>} <br><br>} <br><br>//Use <br>var stu2=new Student(1,'Yangton'); <br> $(stu2.id); <br>$(stu2.name); <br>$(stu2.getAge()); <br>//Define another attribute <br>stu2.sex='pseudo-girl'; <br>$(stu2.sex); <br>//How does dynamic language cross domains? <br>Student.prototype.address="Afghanistan"; <br>$(stu2.address); <br>$("stu2_1 begin..."); <br>var stu2_1 =new Student(1,'杨Dayton'); <br>$(stu2_1.id); <br>$(stu2_1.name); <br>$(stu2_1.getAge()); <br>$(stu2_1.sex); <br>$ (stu2_1.address); //Cross-domain access, b object accesses the attributes of a object<br>//In the definition<br>$("stu2_1 end..."); <br><br>//Option 3 ：json <br>var stu3={id:1,name:'Mao Yanyan',getName:function(){return this.name;}}; <br>$(stu3.id); <br>$(stu3 .name); <br>$(stu3.getName()); <br><br>//var stu2 <br><br>//Many functions in js have the same name as functions in java<br>var str1= new String("abcd") <br>var str2="asdf"; <br>$(str1.indexOf('c')); <br>$(str1.charAt(3)); <br>$ ( str2.charAt(3)); <br>$("absdf".substring(2,4)); <br><br>var day=new Date(); <br>$(day.getYear()) ; <br>$(day.toLocaleString()); <br><br><br>//Let’s talk about arrays again<br>var arr1=new Array(3); <br>arr1[0]=10; <br>arr1[1]=20; <br>arr1[2]=3; <br>_(arr1); <br>arr1[3]=4; <br>// <br>_(arr1); <br><br>//Array 2 <br>var arr2=new Array(234,345,2354,2134,234); <br>_(arr2); <br><br>//Array 3 <br>var arr3=new Array(); <br>arr3[0]=10; <br>arr3[1]=20; <br>arr3[2]=3; <br>_(arr3); <br><br>//Array 4. Recommended writing method <br>var arr4=[]; <br>arr4[0]=10; <br>arr4[1]=20; <br>arr4[2]=3; <br> _(arr4); <br><br>//Array 5. Recommended writing method <br>var arr5=[3254,43,532,45,2345]; <br>_(arr5); <br><br>function add (i,j){ <br>return i j; <br>} <br><br>function add(i,j,k){ <br>return i j k; <br>} <br><br>$( add(1,2));//Automatic recognition of the number of parameters<br><br>var Person=function(id,name) <br>{ <br>this.id=id;//public <br>this .name=name;//public <br>var i=1;//private <br>function test(){//private <br>alert('asdf'); <br>} <br>this.t =function()//public <br>{ <br>return 1; <br>} <br>} <br>var p=new Person(1,"陈新"); <br>$(p.id ); <br>$(p.name); <br>$(p.t());//Normal access<br>$(p.test()); //Cannot access<br></script>