What does “If only the same could be said for every aspect of JavaScript!” mean?

Question

I am trying to learn JavaScript, but my English is not that good.

While reading Simply JavaScript by Kevin Yank & Cameron Adams, I came across this paragraph, and I want to know what one sentence in it means:

Thanks to the wide adoption of the Document Object Model (DOM) standard, accessing HTML elements in your JavaScript code works very similarly in every browser. If only the same could be said for every aspect of JavaScript! As it happens, running JavaScript code in response to an event stands out as one of the few remaining features that are implemented in wildly varying ways in current browsers.

What does "If only the same could be said for every aspect of JavaScript!" mean?

Answer 1

Starting a sentence with "If only" indicates that one wishes the proceeding statement were true. That is, it would be nice if the statement made reflected reality.

For example:

If only everyone laughed at my jokes!

Or:

If only my love and I could be together!

So the person making this statement must have expressed some opinion about a certain aspect of JavaScript--e.g., JavaScript's mechanism for accessing DOM elements is consistent across major browsers--and then expressed the opinion, through the statement you've quoted, that this characteristic (cross-browser consistency) unfortunately does not hold for some other aspects of the language.