如何使用字符串值正确查找（并最终更改）img src属性？

Question

I have the following HTML:

<img id="unique.name.status" class="icon" src="OffStatus.png" alt="OFFLINE" />

At some point a client refreshes and I may need to change the image src and alt with id 'unique.name.status'. First, however, I must be able to find the specific image and, currently, I'm getting an undefined value with the following code:

statusimageId = "#" + user_id + ".status";
alert(statusimageId); // confirmed valid: '#unique.name.status'

statusimageSource = $(statusimageId).attr("src");   // returns 'undefined'
alert(statusimageSource);

NOTE: user_id is a value returned from JSON

Answer 1

jQuery treats its selectors like CSS. Thus, if your statusimageId looks like #USERID.status , then jQuery is looking for the element with ID "USERID" and class "status". You'll want to use a different convention than . to add your "status" flag. Try:

<img id="unique_name_status" class="icon" src="OffStatus.png" alt="OFFLINE" />

and

statusimageId = "#" + user_id + "_status";