How to get WebPart on current page by name/ID with javascript?

Question

I have a page with some webparts on it, I want to get specific one (by name or ID) using client javascript. I try this code

var ctx=SP.ClientContext.get_current();
var web = ctx.get_web();
var site = ctx.get_site();
var theURL = window.location.pathname;
var oFile = web.getFileByServerRelativeUrl(theURL);
var limitedWebPartManager = oFile.getLimitedWebPartManager(SP.WebParts.PersonalizationScope.shared);
var collWebPart = limitedWebPartManager.get_webParts();
ctx.load(collWebPart);
ctx.executeQueryAsync();

How to get webpart by name or id after i get a collection? Maybe there is a easier way to do it?

Answer 1

Once you execute the example you have above, you can (for example) get the title of all web parts on the page by executing this:

var i = collWebPart.get_count()
for (var j=0;j<i;j++)
{ 
    var webPart = collWebPart.get_item(j).get_webPart()
    ctx.load(webPart);
    ctx.executeQueryAsync();

    webPart.get_title();
}

Source: http://msdn.microsoft.com/en-us/library/hh185010.aspx

However, based on your comment above, it sounds like you might be looking for a value from a field from a listitem displayed in the list displayed by this webpart. If that is the case, you might want to try a more direct approach by getting the list, and then the list item, rather than getting the webpart.