fix: input name overriding form method and action checks

[teemingc]

fixes #8467

Replaces form.method with form.getAttribute('method') to avoid collisions with <input name="method"> in the same form.

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[Conduitry]

form.getAttribute('method') will not normalize the method name like form.method will. If someone has method="POST", the code here will not catch that. I don't know whether that would just be a matter of lowercasing the attribute, or stripping whitespace, or what.

Separately, this would (I think) also be susceptible to the extremely contrived situation of an input element name getAttribute. Similar to #7599, we should probably be using HTMLFormData.prototype here.

[teemingc]

form.getAttribute('method') will not normalize the method name like form.method will. If someone has method="POST", the code here will not catch that. I don't know whether that would just be a matter of lowercasing the attribute, or stripping whitespace, or what.

Good catch. Just found that out myself while trying to get the tests to pass.

Separately, this would (I think) also be susceptible to the extremely contrived situation of an input element name getAttribute. Similar to #7599, we should probably be using HTMLFormData.prototype here.

I've tested and it does seem to correctly ignore input elements named "method". But I'll change it anyways for consistency

EDIT: nevermind. HTMLFormElement.prototype.method can't be called

[teemingc]

form.getAttribute('method') will not normalize the method name like form.method will. If someone has method="POST", the code here will not catch that. I don't know whether that would just be a matter of lowercasing the attribute, or stripping whitespace, or what.

Hopefully fixed this issue. Any invalid method attribute value such as method="post " or method="abc", etc. will default to get (similar to the value returned by form.method).

EDIT: Whoops. I understand how action was returned consistently using HTMLFormElement.prototype now. Removed the unnecessary helper method.

Added the same fix for an outstanding form.action check as well.

[dummdidumm]

Thank you!