I have a select with id: param0.typeParameter.
I try to get it with jquery with:
$('#param0.typeParameter');
i get nothing but if it use this
document.getElementById('param0.typeParameter');
that work
3 Answers
To make jQuery select element with ID param0.typeParameter instead of element with ID param0 and class name typeParameter you should use the following:
$('#param0\\.typeParameter');
Official Proof
To use any of the meta-characters ( such as
!"#$%&'()*+,./:;<=>?@[\]^``{|}~) as a literal part of a name, it must be escaped with with two backslashes:\\. For example, an element withid="foo.bar", can use the selector$("#foo\\.bar").
Comments
You can try this instead:
$('[id="param0.typeParameter"]');
Or else the code assumes you want to select an element with id param0 and class typeParameter
4 Comments
Deadron
I believe this makes it a generic attribute selector that will be magnitudes slower than a selector with a properly escaped period that can make use of retrieving the element by its ID.
qwertynl
Hmmm that may be true @Deadron but how slow is "slow"? Is it really that noticeable?
user400654
also, it's selecting an element by id. Since there should only be one of them, you likely only need to perform this once or twice, meaning even if the difference in speed was large, it likely won't be noticeable.
Deadron
@qwertynl While it is obviously implementation specific an ID selection can be assumed to be a constant time operation while a attribute selector would have to scan the document. Depending on the size of your document and the number of times the selector is executed it could have an impact that is trivially avoided.
jQuery uses the CSS-selector language. Which causes "#param0.typeParameter" to be interpretted as an element with id param0 and class typeParameter.
The jQuery statement is more similar to:
document.querySelector("#param0.typeParameter");
1 Comment
poudigne
This is not the solution but the best answer cause of the explanation !!
idname. Dot are used to define a class