使用正则表达式查找没有alt属性的img标记。-Usingregularexpressionstofindimgtagswithoutanaltattribute

0  

This is really tricky, because regular expressions are mostly about matching something that is there. With look-around trickery, you can do things like 'find A that is not preceded/followed by B', etc. But I think the most pragmatic solution for you wouldn't be that.

这很棘手，因为正则表达式主要是关于匹配的东西。使用“查找”技巧，你可以做一些事情，比如“找到一个之前没有/后面没有B的A”等等。

My proposal relies a little bit on your existing code not doing too crazy things, and you might have to fine-tune it, but I think it's a good shot, if you really want to use a RegEx-search for your problem.

我的建议有点依赖于您的现有代码，而不是做太疯狂的事情，您可能需要对它进行微调，但是我认为，如果您真的希望对您的问题使用regex搜索，这是一个很好的尝试。

So what I suggest would be to find all img tags, that can (but don't need to) have all valid attributes for an img-element. Whether that is an approach you can work with is for you to decide.

因此，我建议查找所有img标记，它们可以(但不需要)拥有img元素的所有有效属性。这是否是一种你可以使用的方法，由你来决定。

Proposal:

建议:

//

The current limitations are:

当前的局限性是:

1. It expects your attribute values to be delimited by double quotes,
2. 它期望您的属性值被双引号分隔，
3. It doesn't take into account possible inline on*Event attributes,
4. 它没有考虑到*事件属性的内联，
5. It doesn't find img elements with 'illegal' attributes.
6. 它没有发现含有“非法”属性的img元素。

28  

Building on Mr.Black and Roberts126 answers:

基于布莱克先生和罗伯特126回答:

/(]*)(>)/

This will match an img tag anywhere in the code which either has no alt tag or an alt tag which is not followed by ="" or ='' (i.e. invalid alt tags).

这将匹配代码中任何没有alt标记的img标记或不后跟=""或="的alt标记(即无效的alt标记)。

Breaking it down:

分解:

(          : open capturing group
]*      : match anything following the alt tag up to the closing '>' of the img tag
)          : close capturing group
(>)        : match the closing '>' of the img tag

If your code editor allows search and replace by Regex you can use this in combination with the replace string:

如果您的代码编辑器允许使用Regex进行搜索和替换，那么您可以结合使用替换字符串:

$1 alt=""$3

To find any alt-less img tags and append them with an empty alt tag. This is useful when using spacers or other layout images for HTML emails and the like.

查找无alt标记的img标记并使用空alt标记附加它们。这在使用分隔符或HTML电子邮件等布局图片时非常有用。

11  

Here is what I just tried in my own environment with a massive enterprise code base with some good success (found no false positives but definitely found valid cases):

以下是我在自己的环境中尝试过的方法，使用大量的企业代码库，并取得了一些成功(没有发现假阳性，但肯定找到了有效的案例):

]*\balt=)[^>]*?>

What's going on in this search:

在这个搜索中发生了什么?

1. find the opening of the tag
2. 找到标签的开头
3. look for the absence of zero or more characters that are not the closing bracket while also …
4. 查找不属于结束括号的0或更多字符的缺失，同时……
5. Checking for the absence of of a word that begins with "alt" ("\b" is there for making sure we don't get a mid-word name match on something like a class value) and is followed by "=", then …
6. 检查是否缺少一个以“alt”开头的单词(“\b”是为了确保我们不会在类值之类的东西上获得一个中间单词的名称匹配)，然后是“=”，然后……
7. look for zero or more characters that are not the closing bracket
8. 查找不是结束括号的零或多个字符
9. find the closing bracket
10. 找到个括号

So this will match:

这将匹配:

But it won't match either of these:

但这两者都不匹配:

8  

This works in Eclipse:

这在Eclipse工作:

I'm updating for Section 508 too!

我也在更新第508节!

6  

This worked for me.

这为我工作。

^