Inserting a Variable String into the javascript prototype expression

Question

Pardon me for giving you a confusing title on this problem. I'm really confused and i don't know how to put it in other words.

So here is what I what to accomplish.

I am making a Custom Javascript Object to store data.

I have automated this process and inserted each instance of the object into an array.

I am making a loop statement to invoke the unique property value of each instance of the object.

When I want to use an expression, the property name of the object would be variable since i don't know which one it is.

Basically I need to incorporate a string value into the prototype expression.

e.g

document.getElementById('text').style."fontsize"=value;

since I cannot do this directly, i thought possibly I could use the eval function:

eval('document.getElementById("text").style.' + buttons[i].cssvalue + '="39px";');

but this still doesn't work.

Can this be fixed or ss there an alternative way to accomplish this?

If there are some unclear stuff, please point out and I will try to elaborate.

Thanks in advance.

What does this have to do with prototypejs? Removed that tag. — npup
– npup, Commented May 25, 2010 at 15:12

Jakub Hampl · Accepted Answer · 2010-05-20 00:18:57Z

2

In javascript you can access properties of an object using this notation:

document.getElementById('text').style["fontSize"] = value;

So your code might be:

document.getElementById('text').style[buttons[i].cssvalue] = "39px";

edited May 20, 2010 at 0:18

answered May 20, 2010 at 0:01

Jakub Hampl

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3 Comments

Sune Rasmussen Over a year ago

Yeah, or (...).style[property] = value;

Dennis D Over a year ago

i checked everything else and only this works: document.getElementById("text").style.fontSize="30px";

Anurag Over a year ago

yep it's fontSize, S is caps

codebytom · Accepted Answer · 2017-07-11 12:34:17Z

0

I don't know if this helps or not but I made a utility function which I published to npm which allows you to put in a class name / element along with the CSS properties you're looking at getting. This will then return a Javascript object with the CSS properties and their values within it.

You can find it here on Github and NPM:

GitHub: https://github.com/tjcafferkey/stylerjs

NPM: https://www.npmjs.com/package/stylerjs

answered Jul 11, 2017 at 12:34

codebytom

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Comments

eaglestorm · Accepted Answer · 2010-05-20 00:21:51Z

-1

First thought, look at a Javascript library or framework like JQuery or Dojo they probably have already solved the problem you are looking at. We use JQuery at work but I prefer Dojo's design but it is more targeted at large web applications.

Other than that Jakub's solution should work.

answered May 20, 2010 at 0:21

eaglestorm

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