Show HN:jQuery Signature - Getting a unique signature for a dom element

http://dokeeno.com/v/blog/jquery-signature:-getting-unique-signature-for-dom-element/getting-started

by arunoda • 14 years ago

6 13 14 years ago

dokeeno.com

Myrth• 14 years ago

I love the example page.

arunoda6• 14 years ago

Create a one yourself If you like :P http://dokeeno.com/login

gildas3• 14 years ago

If you set the same value for "class" attribute on DIV elements in the example, the generated selector (i.e. "signature") won't be unique.

BTW, if the selected element has an "id" attribute (with -by definition- a unique value), what is the point to generate the full selector (cf. "Go to Hell" with "bbg" id in the example)?

arunoda6• 14 years ago

You have good valid point here.

for the first one it's kind of a problem. Do you have any sugessions.

For the second one, answer is simple we may have several elements with same id but in different parents. That's why we need something like this.

This is not 100% unique but a innocent try :)

gildas3• 14 years ago

For the first problem, you could test the generated selector to verify it matches only one element. If not you can use, for example, the nth-child pseudo-class to select the right element.

For the second one, specs say that the "id" value must be unique in the entire document [2].

[1] http://www.w3.org/TR/selectors/#structural-pseudos

[2] http://www.w3.org/TR/html401/struct/global.html#h-7.5.2

bdunn• 14 years ago

It looks like this ascends the list of parents for an element to generate a signature. This falls apart if you move an element somewhere else in the DOM - a different signature, but it's really the same node.

IMO the best approach is still to use $.data('my_element', el)

arunoda6• 14 years ago

Yes. You got a valid point here. This does not gonna work for 100% for dynamically generated content. But should work for statically generated contents.

$.data('my_element', el) works if you everything works on the same page without refreshing the window. But I wanted a way to store the signature on a DB and make it highlighted at some point later.

rcsorensen• 14 years ago

I just wrapped up some code I've used in similar situations:

https://github.com/rcs/jQuery.relativeSelector

Instead of going all the way to the body, this will find a selector that works given the structure of the page.

For instance, a page like:

  <body><div id="firstdiv">Target!</div></body>

you can get "#firstdiv" back.

For something like

  <body><div id="#firstClass"><div class="firstClass"><div>Target!</div></div></div></body>

You can get "#firstClass div:eq(0)".

arbales• 14 years ago

I'm not convinced this is actually a good thing to do. As noted by others, its unsuitable for dynamic content, and less direct than `$.data(...)` barring page refresh.

Just not sure what client-side workflow this kind of tool is used in.

Show HN:jQuery Signature - Getting a unique signature for a dom element

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