带有无效ID的getElementById导致脚本退出？ [英] getElementById with invalid ID causes script to exit?
问题描述
我正在写一个使用JavaScript来验证某些表格的网站
我似乎遇到了一些麻烦。该网站使用PHP和
之一的表单，根据情况，其中一个文本输入确实不存在
- PHP没有生成它的HTML。我想要验证脚本验证输入的长度，如果它存在，但是我知道如果我试图检查<的值，我可能会遇到麻烦br />
输入没有先检查输入是否存在所以我尝试使用
代码类似于：
if（document.getElementById（ " someId"）！= null&&
document.getElementById（" someId"）。value.length< 8）
{
alert（" String必须至少8个字符。）;
}
然而，当我在Firefox中尝试时（那个） '到目前为止我唯一尝试过的浏览器
），验证脚本退出，表单提交了
错误，我收到了一条消息JavaScript控制台说我给的
ID无效。我知道它无效！这就是为什么我检查
为空的原因！
我认为如果ID为
$ b $，getElementById（）将返回null b无效。有没有办法在
验证其值之前检查输入是否存在？
-Brandon R.
方法''document.getElementById（" someId"）''返回一个Object的
引用。
so，''document.getElementById（" someId"）。value.length< 8''应该是
modified''document.getElementById（" someId"）。values.length< ; 8''
试试吧：）
bc ****** @ creighton.edu 写道：
if（document.getElementById（" someId"）！= null&&
document.getElementById（" someId"）。value.length< 8）
{
alert（ 字符串必须至少为8个字符。;
}
然而，当我在Firefox中尝试时（那是我唯一的浏览器）到目前为止尝试了
，验证脚本退出，表单提交时出现
错误，我在JavaScript控制台中收到一条消息，说我给的
ID无效。 / blockquote>
请将您传递给getElementById的确切ID值发布并发布
确切的错误消息。这是哪个版本的Firefox？
-
Martin Honnen
http://JavaScript.FAQTs.com/
br ***** @ 163.com 在3/7/2006上午7:37发表以下内容：
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方法''document.getElementById（" someId"）''返回一个Object的
引用。
仅当浏览器具有ID为someID的元素时才支持。
so，''document.getElementById（" someId"）。 value.length< 8''应该被修改''document.getElementById（" someId"）。values.length< 8''
试试吧：）
然后回来问为什么它仍然不起作用？没有
..values属性。
-
Randy
comp.lang .javascript常见问题解答 - http://jibbering.com/faq &新闻组每周
Javascript最佳实践 - http：//www.JavascriptToolbox .com / bestpractices /
I am writing a web site that uses JavaScript to validate certain forms
and I seem to be having some trouble. The site uses PHP and for one of
the forms, depending on the situation, one of of the text inputs does
not exist - the PHP doesn''t generate the HTML for it. I wanted to have
the validation script check the length of the input if it exists but I
knew that I might have trouble if I tried to check the value of the
input without first checking that the input exists so I tried using
code similar to this:
if(document.getElementById("someId")!=null &&
document.getElementById("someId").value.length<8)
{
alert("String must be at least 8 characters.");
}
However, when I try that in Firefox (that''s the only browser I''ve tried
so far), the validation script exits, the form is submitted with
errors, and I get a message in the JavaScript console saying that the
ID that I gave was invalid. I know it''s invalid! That''s why I checked
for null!
I thought that getElementById() would return null if the ID was
invalid. Is there any way to check if the input exists before
validating its value?
-Brandon R.
解决方案the method ''document.getElementById("someId")'' returns a Object''s
reference.
so, ''document.getElementById("someId").value.length<8'' should be
modified ''document.getElementById("someId").values.length<8 ''
just try it : )
bc******@creighton.edu wrote:
if(document.getElementById("someId")!=null &&
document.getElementById("someId").value.length<8)
{
alert("String must be at least 8 characters.");
}
However, when I try that in Firefox (that''s the only browser I''ve tried
so far), the validation script exits, the form is submitted with
errors, and I get a message in the JavaScript console saying that the
ID that I gave was invalid.
Please post the exact id value you pass to getElementById and post the
exact error message you get. Which version of Firefox is that?
--
Martin Honnen
http://JavaScript.FAQTs.com/
br*****@163.com said the following on 3/7/2006 7:37 AM:
Please quote what you are replying to.
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the method ''document.getElementById("someId")'' returns a Object''s
reference.
Only if the browser has an element with an ID of "someID".
so, ''document.getElementById("someId").value.length<8'' should be
modified ''document.getElementById("someId").values.length<8 ''
just try it : )
And then come back and ask why it still doesn''t work? There is no
..values property.
--
Randy
comp.lang.javascript FAQ - http://jibbering.com/faq & newsgroup weekly
Javascript Best Practices - http://www.JavascriptToolbox.com/bestpractices/
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