[英]When submitting a form for JavaScript validation what does the return before the function call do?
<form name="myForm" action="demo_form.asp" onsubmit="return validateForm();" method="post">
为什么validateForm()
之前必须有return
?
If you don't use return
, Javascript will call validateForm
but will throw away the return value. 如果不使用
return
,则Javascript会调用validateForm
但会丢弃返回值。
If onsubmit
returns false
the form won't be submitted. 如果
onsubmit
返回false
,则不会提交表单。
The default submit action of the <form>
can be stopped if the onsubmit
function returns false
. 如果
onsubmit
函数返回false
则可以停止<form>
的默认提交动作。
The value of the onsubmit
attribute is treated like a function body, so the return
is needed so that the form isn't submitted if it's not valid. onsubmit
属性的值被视为函数体,因此需要return
,以便在表单无效时不提交表单。
Basically, what's happening in that inline handler is this: 基本上,该内联处理程序中发生的事情是这样的:
<button id="submit-button" type="submit" onclick="return validate()"></button>
var button = document.getElementById("submit-button");
button.onclick; // function () { return validate(); }
Versus: 与:
<button id="submit-button" type="submit" onclick="validate(event)"></button>
var button = document.getElementById("submit-button");
button.onclick; // equals function (event) { validate(event); }
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