javascript callback

2023-08-05 13:46:34

JSON

{ "name":"John", "age":30, "city":"New York"}

JSON.parse(json_str)

获取时间

function getTime(){

	//第一种  1498627266000

	var millisecond =Date.parse(new Date());

	console.log(millisecond);

	//第二种   1498627266558

	var millisecond =(new Date()).valueOf();

	console.log(millisecond);

	//第三种   1498627266558

	var millisecond =new Date().getTime();

	console.log(millisecond);

	var myDate = new Date();

	console.log(myDate.getFullYear()); //获取完整的年份(4位,1970-????)

	console.log(myDate.getMonth()); //获取当前月份(0-11,0代表1月)

	console.log(myDate.getDate()); //获取当前日(1-31)

	console.log(myDate.getDay()); //获取当前星期X(0-6,0代表星期天)

	console.log(myDate.getTime()); //获取当前时间(从1970.1.1开始的毫秒数)

	console.log(myDate.getHours()); //获取当前小时数(0-23)

	console.log(myDate.getMinutes()); //获取当前分钟数(0-59)

	console.log(myDate.getSeconds()); //获取当前秒数(0-59)

	console.log(myDate.getMilliseconds()); //获取当前毫秒数(0-999)

	console.log(myDate.toLocaleDateString()); //获取当前日期

	console.log(myDate.toLocaleTimeString()); //获取当前时间

	console.log(myDate.toLocaleString()); //获取日期与时间

}

reading

https://javascriptissexy.com/understand-javascript-callback-functions-and-use-them/

MDN web docs

jquery

https://api.jquery.com/jquery.get/

选择器

html 标签选择

$('div')

class 选择器

$('.class_name')

id 选择器

$('#id_name')

fetch

About the Request.mode'no-cors' (from MDN, emphasis mine)

Prevents the method from being anything other than HEAD, GET or POST. If any ServiceWorkers intercept these requests, they may not add or override any headers except for these. In addition, JavaScript may not access any properties of the resulting Response. This ensures that ServiceWorkers do not affect the semantics of the Web and prevents security and privacy issues arising from leaking data across domains.

So this will enable the request, but will make the Response as opaque, i.e, you won't be able to get anything from it, except knowing that the target is there.

Since you are trying to fetch a cross-origin domain, nothing much to do than a proxy routing.

var quizUrl = 'http://www.lipsum.com/';

fetch(quizUrl, {

  mode: 'no-cors',

  method: 'get'

}).then(function(response) {

  console.log(response.type)

}).catch(function(err) {

  console.log(err) // this won't trigger because there is no actual error

});

Notice you're dealing with a Response object. You need to basically read the response stream with Response.json() or Response.text() (or via other methods) in order to see your data. Otherwise your response body will always appear as a locked readable stream.

fetch('https://api.ipify.org?format=json')

.then(response=>response.json())

.then‌(data=>{ console.log(data); })

If this gives you unexpected results, you may want to inspect your response with Postman.

fetch(url, {

    method: 'POST',

    headers: {

        'Accept': 'application/json',

        'Content-Type': 'application/json'

    },

    body: JSON.stringify({

        email: login,

        password: password,

    })

})

    .then(function (a) {

        return a.json(); // call the json method on the response to get JSON

    })

    .then(function (json) {

        console.log(json)

    })

Creating a div element in jQuery

div = $("<div>").html("Loading......");

$("body").prepend(div);

$('#parent').append('<div>hello</div>');

// or

$('<div>hello</div>').appendTo('#parent');

jQuery('<div/>', {

    id: 'some-id',

    class: 'some-class',

    title: 'now this div has a title!'

}).appendTo('#mySelector');

jQuery(document.createElement("h1")).text("My H1 Text");

<div id="targetDIV" style="border: 1px solid Red">

    This text is surrounded by a DIV tag whose id is "targetDIV".

</div>

//Way 1: appendTo()

<script type="text/javascript">

    $("<div>hello * users</div>").appendTo("#targetDIV"); //appendTo: Append at inside bottom

</script>

//Way 2: prependTo()

<script type="text/javascript">

    $("<div>Hello, Stack Overflow users</div>").prependTo("#targetDIV"); //prependTo: Append at inside top

</script>

//Way 3: html()

<script type="text/javascript">

    $("#targetDIV").html("<div>Hello, Stack Overflow users</div>"); //.html(): Clean HTML inside and append

</script>

//Way 4: append()

<script type="text/javascript">

    $("#targetDIV").append("<div>Hello, Stack Overflow users</div>"); //Same as appendTo

</script>

动态添加表格行

var $row = $('<tr>'+

      '<td>'+obj.Message+'</td>'+

      '<td>'+obj.Error+'</td>'+

      '<td>'+obj.Detail+'</td>'+

      '</tr>');

if(obj.Type=='Error') {

    $row.append('<td>'+ obj.ErrorCode+'</td>');

}

$('table> tbody:last').append($row);

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