当通过javascript定义时，onclick的行为有所不同 [英] onclick behaves differently when defined via javascript
问题描述
http://www.frostjedi.com /terra/scrip...his-alert.html
http://www.frostjedi.com/terra/scrip...is-alert2.html
为什么，当你点击在黑匣子里，做警示框说不同的东西是什么？他们不应该说同样的话吗？
http://www.frostjedi.com/terra/scrip...his-alert.html
http://www.frostjedi.com/terra/scrip...is-alert2.html
Why, when you click in the black box, do the alert boxes say different
things? Shouldn''t they say the same thing?
推荐答案
2008年9月25日星期四15:45:50 -0700，yawnmoth写道：
On Thu, 25 Sep 2008 15:45:50 -0700, yawnmoth wrote:
http： //www.frostjedi.com/terra/scrip...his-alert.html
http://www.frostjedi.com/terra/scrip...is-alert2.html
为什么，当你在黑匣子里点击时，警告框会说不同的
东西？他们不应该说同样的话吗？
http://www.frostjedi.com/terra/scrip...his-alert.html
http://www.frostjedi.com/terra/scrip...is-alert2.html
Why, when you click in the black box, do the alert boxes say different
things? Shouldn''t they say the same thing?
你的问题在这里：
< div onclick =" test（）"< / div>
它不同于：
< div onclick = test< / div>
第一个表单运行"测试（）"在全球范围内运作。
全局对象没有名为tagName的属性。
第二种形式（以及你的第二个例子）使用函数
参考，并在div的上下文中运行。
了解脚本运行的环境对于理解什么是这个是必不可少的。是指。
Your problem is here:
<div onclick="test()"</div>
It is NOT the same as:
<div onclick=test</div>
The first form runs the "test()" function within the global context. The
Global Object does not have a property called tagName.
The second form (as well as your second example) use a function
reference, and runs within the context of the div.
Understanding the environment the script runs in is essential to
understanding what "this" refers to.
当为元素提供内在事件属性时（假设
被识别，等等），例如： -
< div onclick =" test（）"< / div>
- 浏览器使用字符串值（在本例中为text（））作为
正文文本的一个函数，它创建并分配给
对应的表示属性
DOM中的元素。所以这里的浏览器相当于： -
divRef.onclick = function（event）{
test（）;
};
（有或没有 - event - 形式参数，取决于
浏览器）
浏览器执行此操作与执行
相当于： -
divRef.onclick = test;
- 是当浏览器调用函数时它调用函数
- divRef.onclick（）; - （有或没有事件对象作为
参数，具体取决于浏览器）所以 - this - 值为
执行分配给 - divRef的函数。 onclick - 是对DIV元素的一个
引用，但分配的函数是不同的。
一个是浏览器创建的函数（该函数将
然后调用 - test - ）而另一个是测试本身。如果
被调用的函数是由浏览器创建的函数那么当它被调用时 - 测试 - 它会以这样的方式实现 - 这个 - 价值
在该调用中是对全局对象的引用。
When an intrinsic event attribute is provided for an element (assuming
it is recognised, etc.), such as:-
<div onclick="test()"</div>
- the browser uses the string value (the "text()" in this case) as the
body text of a function that it creates and assigned to the
corresponding property of the representation of the element in the
DOM. So what the browser does here is the equivalent of:-
divRef.onclick = function(event){
test();
};
(with or without the - event - formal parameter, depending on the
browser)
The difference between the browser doing this and your doing the
equivalent of:-
divRef.onclick = test;
- is that when the browser calls the function it calls the function as
- divRef.onclick(); - (with or without an event object as the
argument, depending on the browser) so the - this - value for the
execution of the function assigned to - divRef.onclick - is a
reference to the DIV element, but the function assigned is different.
One is the function that the browser created (the function that will
then call - test -) and the other is test itself. In the event that
the function called is the one created by the browser then when it
calls - test - it does so in a way that will make the - this - value
inside that call be a reference to the global object.
9月26日，12：43 * pm，Henry< rcornf。 .. @ raindrop.co.ukwrote：
On Sep 26, 12:43*pm, Henry <rcornf...@raindrop.co.ukwrote:
为元素提供内在事件属性时（假设
被识别，等等。），例如： -
< div onclick =" test（）"< / div>
- 浏览器使用字符串值（在本例中为text（））作为它创建并分配给
对应属性的函数的
正文文本
DOM中元素的表示形式。所以这里的浏览器相当于： -
divRef.onclick = function（event）{
* * test（）;
};
When an intrinsic event attribute is provided for an element (assuming
it is recognised, etc.), such as:-
<div onclick="test()"</div>
- the browser uses the string value (the "text()" in this case) as the
body text of a function that it creates and assigned to the
corresponding property of the representation of the element in the
DOM. So what the browser does here is the equivalent of:-
divRef.onclick = function(event){
* * test();
};
纠正我，如果我弄错了，但我想我曾经在某个地方看过它
执行文本的eval（）：喜欢（在这种情况下）eval（''test（）''）...？
-
Jorge。
Correct me if I''m mistaken, but I think I once read somewhere that it
does an eval() of the text: like (in this case) eval(''test()'')... ?
--
Jorge.
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