I have a form DOM element:
var virDom = document.getElementsByTagName("form")[0];
virDom has two fields with IDs creditId and pwdId... I can access virDom.creditId without any issue, but virDom.pwdId.. is failing with a syntax error, because of the periods contained in the name.
How can I access such properties?
Use bracket notation:
virDom['creditId']
virDom['pwdId..']
This applies to any object, and it is particularly useful for non-identifier-safe characters and also for accessing keys that you may not know ahead of time.
For a nested object with a special character like below,
var details = {"name-details": {"first-name": "Kiran"}}
use
console.log(details["name-details"]["first-name"])
I am using this script to make a style object of all the inherited, etc. styles.
var style = css($(this));
alert (style.width);
alert (style.text-align);
With the following, the first alert will work fine, but the second one doesn't... it's interpreting the - as a minus I assume. The debugger says 'uncaught reference error'. I can't put quotes around it, though, because it isn't a string. So how do I use this object property?
Look at the comments. You will see that for CSS properties, the key notation is not compatible with a number of properties. Using the camel case key notation therefore is the current way:
obj.style-attr // would become
obj["styleAttr"]
Use key notation rather than dot
style["text-align"]
All arrays in JavaScript are objects and all objects are just associative arrays. This means you can refer to a place in an object just as you would refer to a key in an array.
arr[0]
or the object
obj["method"] == obj.method
A couple things to remember when accessing properties this way:
they are evaluated so use strings unless you are doing something with a counter or using dynamic method names.
This means obj[method] would give you an undefined error while obj["method"] would not
You must use this notation if you are using characters that are not allowed in JavaScript variables.
This regex pretty much sums it up:
[a-zA-Z_$][0-9a-zA-Z_$]*
The answer to the original question is: place the property name in quotes and use array style indexing:
obj['property-with-hyphens'];
Several have pointed out that the property you are interested in is a CSS property. CSS properties that have hyphens are automatically converted to camel casing. In that case you must use the camel cased name like:
style.textAlign;
However this solution only works for CSS properties. For example,
obj['a-b'] = 2;
alert(obj.aB); // undefined
alert(obj['a-b']); // 2
CSS properties with a - are represented in camelCase in JavaScript objects. That would be:
alert( style.textAlign );
You could also use a bracket notation to use the string:
alert( style['text-align'] );
Property names may only contain characters, numbers, the well known $ sign and the _ (thanks to pimvdb).
Use brackets:
var notTheFlippingStyleObject = {
'a-b': 1
};
console.log(notTheFlippingStyleObject["a-b"] === 1); // true
More information on objects: MDN
NOTE: If you are accessing the style object, CSSStyleDeclaration, you must use camelCase to access it from JavaScript. More information is here.
alert(style.textAlign)
or
alert(style["textAlign"]);
To directly answer the question: style['text-align'] is how you would reference a property with a hyphen in it. But style.textAlign (or style['textAlign']) is what should be used in this case.
Hyphenated style properties are referenced via camelCase in JavaScript, so use style.textAlign.
To solve your problem: The CSS properties with hyphens in them are represented by JavaScript properties in camelCase to avoid this problem. You want: style.textAlign.
To answer the question: Use square bracket notation: obj.prop is the same as obj["prop"] so you can access property names using strings and use characters that are forbidden in identifiers.
I think in the case of CSS styles they get changed to camelCase in JavaScript, so test-align becomes textAlign.
In the general case, where you want to access a property that contains non-standard characters, you use array-style: ['text-align']
The object property names are not one-to-one matches for the CSS names.
At first, I wondered why the solution didn't work on my end:
api['data-sitekey'] // Returns undefined
...later on I figured out that accessing data attributes was different:
It should be like this:
var api = document.getElementById("some-api");
api.dataset.sitekey
I have a form DOM element:
var virDom = document.getElementsByTagName("form")[0];
virDom has two fields with IDs creditId and pwdId... I can access virDom.creditId without any issue, but virDom.pwdId.. is failing with a syntax error, because of the periods contained in the name.
How can I access such properties?
Use bracket notation:
virDom['creditId']
virDom['pwdId..']
This applies to any object, and it is particularly useful for non-identifier-safe characters and also for accessing keys that you may not know ahead of time.
For a nested object with a special character like below,
var details = {"name-details": {"first-name": "Kiran"}}
use
console.log(details["name-details"]["first-name"])
finalVariables() returns an object that contains data accessible by .dataName notation i.e. finalVariables().mainViewWindow0 returns the string stored for mainViewWindow0. I'm trying to access mainViewWindow0 using a dynamically created variable, but for obvious reasons this doesn't work so well with dot notation, but I don't know how to work around it. Help to be had for me?
Please ignore the poor coding practice of having a hard-coded number in there; I promise to get rid of it later
activePane = dot.id.substring(6); //gets dot # and sets it as active pane
var tempForPaneNumber = "mainViewWindow" + activePane + "";
document.getElementById("mainViewWindowContent").innerHTML = finalVariables().###this is where I want to use
the string from "tempForPaneNumber" to access ###
finalVariables[tempForPainNumber]()
Should do the trick if I understand correctly.
In Javascript you can access properties of an object either through the dot notation or through the use of brackets to specify the identifier for the property so myVar.foo is equivalent to myVar['foo']. Therefore, if I understand what you are asking correctly you want to use finalVariables()[tempForPaneNumber]()
So I have a string "getNumber":
I would like to use this string as a method for an object: myObj.getNumber()
Is that possible?
Thanks
As simple as:
myObj['getNumber']();
There two ways to access value from js object .. one is dot notation . and other is square bracket notation [], which allows access to properties containing special characters and selection of properties using variables.
var key = 'getNumber';
myObj[key]();
More information on Mozilla, working with object guide.