Category Archives: Javasript

Jquery.min.js import project error [How to Solve]

Solution:

Select the whole project for verification: a total of 2 steps

Note: be sure to close the JS file that reported an error, otherwise the error may still be reported in the verification. In case, close all open files in the workspace

Error in JS function referencing public page [How to Solve]

For the website, there are a large number of sharing modules between many pages, such as page header, footer and user bar. Many times, in order to be convenient and easy, we write functions in public modules and call them in other pages. However, when we reference public JS functions, some can be referenced, but some report errors this is because of the problem of JS loading, that is, when the current page is loaded, but some public pages reference public JS before loading, it will report that this function is not found

The results are as follows:

JS referencing public footer

The results are as follows:

from the above two examples, we can know that the loading order of JS is from top to bottom. The header is loaded first – the current page – the footer. Finally, if all the current pages reference the footer that has not been loaded, JS will report “F”_public is not defined”

The solution is as follows:

$(document).ready(function () {
        f_public();
})

when the DOM (document object model) has been loaded and the page (including image) has been completely rendered, the ready event will occur; This function is not called until the footer is loaded

page execution sequence in JS

1: Use $(function) {} of jQuery

2: Use $(document). Ready (function() {}) of jQuery; There is no essential difference between the first two. The first is the abbreviation of the second. The second is to execute the method after the document is loaded

3: Use $(window). Load (function() {}) of jQuery

4: Use window. Onload = function() {} the third and fourth methods wait until the whole window is loaded to execute the method body. There is no difference between the two, except that one uses DOM objects and the other uses jQuery objects

5: Statically bind the onload event on the tag, & lt; body onload=”aaa()”> When the body is loaded, the AAA () method is executed

So, what is the implementation order of these five methods

Through the following code verification, it is found that:

Use $(function) {} of 1: jQuery and $(document). Ready (function() {}) of 2: jQuery; No matter where the position is placed, the other three methods always take precedence (the reason is that these two methods are executed after the document is loaded, and the last three methods are executed after the whole window page is loaded). The execution order between the two is who is at the top and who takes precedence

Use $(window). Load (function() {}) of 3: jQuery

4: window. Onload = function bbb() {} always takes precedence over & lt; body onload=”aaa()”> Execution. Their execution order is also based on who is at the top and who is first

Use 5: & lt; body onload=”aaa()”> Always last

<script type='text/javascript'>

　　window.onload = function(){
　　　　alert("Page loading completed====》onload");
　　}

　　$(window).load(function(){
　　　　alert("jquery===》window load" );
　　})

　　$(document).ready(function () {
　　　　alert("jquery====》document ready");
　　});

　　$(function(){
　　　　alert("jquery====》document onload");
　　});

　　function aaa(){
　　　　alert("Static labels====》onload");
　　}

</script>

<body onload="aaa()">

</body>

How to Solve Vue Error: NavigationDuplicated

1. Error information

This error report does not affect the function. If you feel uncomfortable, you can solve it

2. Solutions

Add the following sentences in main. JS


import Router from 'vue-router'
const originalPush = Router.prototype.push
Router.prototype.push = function push(location) {
  return originalPush.call(this, location).catch(err => err)
}

Done!

[Solved] Node.js runs ES6 default import file error: import m1 from’./m1.js’ ^^ SyntaxError: Unexpected identifier

JQuery Ajax crossdomain cannot be used in IE [How to Solve]

The code is as follows:

$.ajax({
		type:'post',
		url:url,
		data:data,
		dataType:'json',
		xhrFields:{
withCredentials:true
/*
Corresponds to the code in the server
response.addHeader("Access-Control-Allow-Credentials","true");
		response.addHeader("Access-Control-Allow-Origin",origin);
*/
},
crossDomain:true,
success:function(res){
	//。。。
},
error:function(resData){
	//。。。。
}
	});

Open chrome, open fiddler, visit the page, click the button to run, the browser seems to be normal, Fiddler gets an http200 ~! It seems that cross domain access can be achieved by setting crossdomain = true, but it is not perfect

Open IE, test again,,, report an error!?There is no response in fiddler, even the request is not sent out. Strange?Google… Found in an article in stackoverflow:

http://stackoverflow.com/questions/3362474/jquery-ajax-fails-in-ie-on-cross-domain-calls

In other words, IE8 uses the so-called xdomainrequest instead of XMLHttpRequest, but jQuery only supports XMLHttpRequest

At present, the best solution is to use jsonp