Summary of common javascript functions_javascript skills

1. The meaning of path symbols
src="/js/jquery.js", "../" The slash means an absolute path, which represents the root directory of the website.
Others such as "./", "../", "jquery.js", "js/jquery.js", etc. represent paths relative to the current web page and are relative paths.
2. Get the root directory of the website

//The url of the website is: http://www.A.COM?a=12 String.prototype.getQuery = function (name) { var reg = new RegExp("(^|&)" name "=([^&]*)(&|$)");
var r = this.substr(this.indexOf("?" ) 1).match(reg); 4. Functions in js
document.write(Math.round(0.60) "
") 1 document.write(Math.round(0.50) "
") 1
document.write(Math.round(0.49) "
") 0
document. write(Math.round(-4.40) "
") -4 document.write(Math.floor(Math.random()*11)) The floor() method and random() of the Math object to return a random number between 0 and 10

5.1 Merge arrays into arrays concat merges arrays to generate a new array , the original array remains unchangedCopy code


The code is as follows:

var arr = new Array(3 )//Define array
arr[0] = "George" arr[1] = "John"
arr[2] = "Thomas" 5.2 Arrays are combined into string join. The default is "," connection, which can be specified, such as join(".")

var patt1=new RegExp("e"); document .write(patt1.test("The best things in life are free"));

The code is as follows:

/*
The following is an example of using the onSubmit event. When the user clicks the confirm button in the form, the checkForm() function is called. If the field value is invalid, the submission will be cancelled. The return value of the checkForm() function is true or false. If the return value is true, submit the form, otherwise cancel the submission. */

8. cookie
8.1 Create

Copy code The code is as follows:

function setCookie(c_name,value,expiredays)
{
var exdate=new Date()
exdate.setDate(exdate.getDate() expiredays)
document.cookie=c_name "=" escape(value)
((expiredays==null) ? "" : ";expires=" exdate.toGMTString())
}

8.2 Read

Copy code The code is as follows:

function getCookie(c_name)
{
if ( document.cookie.length>0)
{
c_start=document.cookie.indexOf(c_name "=")
if (c_start!=-1)
{
c_start=c_start c_name .length 1
c_end=document.cookie.indexOf(";",c_start)
if (c_end==-1) c_end=document.cookie.length
return unescape(document.cookie.substring( c_start,c_end))
}
}
return ""
}

9. Timing
setTimeout() Start timing
var t=setTimeout("javascript statement", milliseconds) clearTimeout(t) //Stop timing
10. Open the website
10.1 Open the website in another window window.open()

Copy code The code is as follows:

function openW(v){
var str = 'width=200,height=200,left=200,top=200,status=no,scrollbars=no,'
str = 'menubar=no,toolbar=no,resizable=no,location=no'
window.open(v,'',str);
}

10.2 Open the website in the same window
window.location.href ='http://www.sohu .com' ;
11. Object
11.1 Object definition, destruction

Copy code The code is as follows:

var oObject = new Object;
// do something with the object here
oObject = null;

11.2 Defining Classes

Copy code The code is as follows:

function Cat(name,color){
　this.name = name;
This.color = color;
this.type = "Feline";


11.3 Use JSON to construct an object

Copy code The code is as follows:

var People = {

Create: function (name, age) {
this.name = name;
this.age = age;
},
SayHello: function ( ) {
alert("Hello,My name is " this.name ".I am " this.age);
}
};


11.4 Use prototype to construct An object

Copy code The code is as follows:

var Person = function (name, age) {

this.name = name;
this.age = age;
};
Person.prototype.Introduce = function () {
alert("My name is " this.name " .I'm " this.age);
}