我在HTML页面中见过很多这样的链接:
<a href='#' onclick='someFunc(3.1415926); return false;'>Click here !</a>
这里return false的效果是什么?
而且,我通常不会在按钮中看到这种情况。
这在任何地方都指定了吗?在w3.org的一些规范中?
我在HTML页面中见过很多这样的链接:
<a href='#' onclick='someFunc(3.1415926); return false;'>Click here !</a>
这里return false的效果是什么?
而且,我通常不会在按钮中看到这种情况。
这在任何地方都指定了吗?在w3.org的一些规范中?
当前回答
我很惊讶没有人提到onmousedown而不是onclick。的
onclick = '返回假'
没有捕捉浏览器的默认行为,导致(有时不需要的)文本选择发生鼠标下拉,但是
onmousedown = '返回假'
所做的事。
In other words, when I click on a button, its text sometimes becomes accidentally selected changing the look of the button, that may be unwanted. That is the default behaviour that we are trying to prevent here. However, the mousedown event is registered before click, so if you only prevent that behaviour inside your click handler, it will not affect the unwanted selection arising from the mousedown event. So the text still gets selected. However, preventing default for the mousedown event will do the job.
参见event.preventDefault() vs. return false
其他回答
你可以从下面的例子中看出区别:
<a href="http://www.google.co.uk/" onclick="return (confirm('Follow this link?'))">Google</a>
单击“ok”返回true,然后是链接。点击“取消”返回false,并且不遵循链接。如果javascript被禁用,链接是正常的。
从JavaScript事件中返回false通常会取消“默认”行为——在链接的情况下,它告诉浏览器不要跟踪该链接。
当使用表单时,我们可以使用'return false'来阻止提交。
function checkForm() {
// return true to submit, return false to prevent submitting
}
<form onsubmit="return checkForm()">
...
</form>
我很惊讶没有人提到onmousedown而不是onclick。的
onclick = '返回假'
没有捕捉浏览器的默认行为,导致(有时不需要的)文本选择发生鼠标下拉,但是
onmousedown = '返回假'
所做的事。
In other words, when I click on a button, its text sometimes becomes accidentally selected changing the look of the button, that may be unwanted. That is the default behaviour that we are trying to prevent here. However, the mousedown event is registered before click, so if you only prevent that behaviour inside your click handler, it will not affect the unwanted selection arising from the mousedown event. So the text still gets selected. However, preventing default for the mousedown event will do the job.
参见event.preventDefault() vs. return false
返回false表示不采取默认操作,在<a href>的情况下,默认操作是遵循链接。当你对onclick返回false时,href将被忽略。