對(duì)象與數(shù)組的轉(zhuǎn)換 http://www.cnblogs.com/lijuntao/p/6604276.html
遍歷
Paste_Image.png
- each() 循環(huán)遍歷
var arr = [ "one", "two", "three", "four"];
$.each(arr, function(){
alert(this);
});
//上面這個(gè)each輸出的結(jié)果分別為:one,two,three,four
var arr1 = [[1, 4, 3], [4, 6, 6], [7, 20, 9]]
$.each(arr1, function(i, item){
alert(item[0]);
});
//其實(shí)arr1為一個(gè)二維數(shù)組赐写,item相當(dāng)于取每一個(gè)一維數(shù)組,
//item[0]相對(duì)于取每一個(gè)一維數(shù)組里的第一個(gè)值
//所以上面這個(gè)each輸出分別為:1 4 7
var obj = { one:1, two:2, three:3, four:4};
$.each(obj, function(i) {
alert(obj[i]);
});
//這個(gè)each就有更厲害了,能循環(huán)每一個(gè)屬性
//輸出結(jié)果為:1 2 3 4
- map():返回一個(gè)由原數(shù)組中每個(gè)元素調(diào)用一個(gè)指定方法后的返回值組成的新數(shù)組
Paste_Image.png
- 保留兩位小數(shù): num.toFixed(2)
- select動(dòng)態(tài)添加option:
var data = [
{name:"aadfffffffffffaaa",value:"1"},
{name:"bbbbb",value:"2"},
{name:"ccccc",value:"3"},
{name:"aaaaa",value:"1"},
{name:"ccccc",value:"3"},
{name:"aaaaa",value:"1"},
{name:"bbbbb",value:"2"},
{name:"ccccc",value:"3"},
];
var ops = data.map(function(item){
var op = $("<option></option>");
op.val(item.value);
op.text(item.name);
return op;
});
jQuery與JS的某些差異
- http://blog.csdn.net/duanshuyong/article/details/7562423/
- jquery 把 js 獲取的 dom 放到數(shù)組了
var aa = document.getElementById("qrcode");
var bb = $("#qrcode");
var cc= bb[0]
console.log(aa);
console.log(bb);
console.log(cc);