Unclosed square bracket doesn't throw error in jquery

问题

$('#parent_tab [href="#tab1"').click();

The above line works fine and the tab gets selected in other browsers but not safari. I had to close the square bracket of href as follows in order to make it work in Safari.

$('#parent_tab [href="#tab1"]').click();

Why did jquery not throw an error when the square bracket is not closed?

回答1:

This looks like it's a Safari issue. Another reason is because the closing bracket is inside the jQuery selector. Safari might be concerned only with JavaScript code outside jQuery selector. It is just a text that can have different format and jQuery just tries to interpret it.

You can also try the following code if it will throw an error.

$("#parent_tab [href='#tab1'").click();

回答2:

The CSS spec says that it's okay to leave off the bracket. Since jQuery passes the selector along to the native querySelectorAll first for performance, and that method does not throw an error (plus it returns the correct element), the missing bracket isn't detected. If you used a jQuery-specific selector like :animated the string would go through jQuery's Sizzle selector engine and you would get an error.

https://bugs.jquery.com/ticket/15199