<?php
class Record {
protected static $tableName = 'base';
public static function getTableName() {
echo self::$tableName;
}
}
class User extends Record {
protected static $tableName = 'users';
}
User::getTableName();
它显示:基础
题:
我知道我可以通过改变这一行echo self::$tableName;来改变问题echo static::$tableName;,它被称为'后期静态绑定',我在这里阅读了doc ,但仍然不太了解它.所以你能给我一些解释:
一个.为什么这行代码echo self::$tableName;显示:base？
湾 为什么这行代码echo static::$tableName;显示:用户？
我试图在js中理解事件(例如:click,keyPress ...).但是当我在网上学习时,我看到它在"DOM事件"中提到了很多.所以我的问题是js事件和DOM事件一样吗？如果没有,有什么区别？
<script>
var mango = new Object ();
mango.color = "yellow";
mango.shape= "round";
mango.sweetness = 8;
Object.prototype.howSweetAmI = function () {
console.log("Hmm Hmm Good");
}
console.log(mango);
</script>
题:
我可以改变这一行: Object.prototype.howSweetAmIto mango.howSweetAmI,并且它们都可以工作.但它们之间有什么区别？通常我们使用哪种方式来创建方法？
我正在使用Eclipse for PHP Developers Version:3.0.2.我怎么能从远程svn(TortoiseSVN)看看.我在网上搜索,但它确实有帮助,我试图导入,但没有像'来自svn'这样的选项.
以下代码摘自MDN页面Function.prototype.apply:
Function.prototype.construct = function (aArgs) {
var fConstructor = this,
fNewConstr = function () { fConstructor.apply(this, aArgs); };
fNewConstr.prototype = fConstructor.prototype;
return new fNewConstr();
};
function MyConstructor() {
for (var nProp = 0; nProp < arguments.length; nProp++) {
this["property" + nProp] = arguments[nProp];
}
}
var myArray = [4, "Hello world!", false];
var myInstance = MyConstructor.construct(myArray);
alert(myInstance.property1); // alerts "Hello world!"
alert(myInstance instanceof MyConstructor); // alerts "true"
alert(myInstance.constructor); // alerts "MyConstructor"
我对这段代码有两个问题:
我知道如果我使用var myInstance = new MyConstructor(); …
<script>
function makeArray(arg1, arg2){
return [ this, arg1, arg2 ];
}
alert(window.makeArray('one', 'two'));
</script>
题:
上面脚本的输出是:[Object Window],一,二,如果我改变了返回[this,arg1,arg2]; 返回(this,arg1,arg2); 输出是:两个.那么return []和return()之间有什么区别？
HTML:
<div id="id1">
this is my text1.
</div>
<div id="id2">
this is my text2.
</div>
CSS:
<style>
#id1 {
margin: 0 auto;
width: 600px;
background-color:#00FFCC;
}
#id2 {
margin: 0 auto;
width: 600px;
background-color:#FFCCCC;
}
</style>
在前面,它显示:
this is my text1. (green background)
this is my text2. (pink background)
现在,如果我想要它显示如下:
this is my text1. this is my text2. (green background)
empty in pink background
所以,如果不改变HTML代码,是否有可能只通过CSS发生？基本上我想要做的是将文本移动this is my text2.到第一个div:<div id="id1"></div>
<!doctype html>
<html>
<head>
<meta charset="utf-8" />
<title>Demo</title>
<script src="//ajax.googleapis.com/ajax/libs/jquery/1.9.1/jquery.min.js"></script>
<script>
var headings = $('h3');
var paras = $('p');
paras.hide().eq(0).show();
headings.click(function() {
var cur = $(this); //save the element that has been clicked for easy referal
cur.siblings('p').hide(); //hide all the paragraphs
cur.next('p').show(); //get the next paragraph after the clicked header and show it
});
</script>
<style type="text/css">
p,h3 {margin: 0; padding: 0;}
p {height: 150px; width: 200px; border: 1px solid black;}
h3 {height: 50px; width: 200px; background-color: blue; color: white; …<script>
var person = function () {
// Private
var name = "David";
return {
getName : function () {
return name;
},
setName : function (newName) {
name = newName;
}
};
}();
console.log(person.name);
</script>
题:
为什么它显示:在控制台中未定义？