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JavaScript JavaScript Loops Working with 'for' Loops Dynamically Display HTML with a Loop

html += `<div>${i}</div> logic behind +=?

I was able to complete the for loop without problem, however I'm quite thick in the head and couldn't grasp the logic behind the "+=" in html += <div>${i}</div>

I know that "+=" produces ${i} from zero to ten, and a "=" only prints out a number ten, but I just can't wrap my head around it.

It'll be awesome if someone could tell me how this logic translates to easy words

2 Answers

html is initialized as an empty string. Each time through the for loop, the += operator adds the new string element. The += operator is just a shorthand way to write it.

html += <div>${i}</div>;

Would be the same as:

html = html + <div>${i}</div>;

So each time through the for loop, the html variable is updated by concatenating the old html string with a new string.

Hopefully this makes a little more sense!

I think the part where I don't understand is that: which part of the code allows the "html" before addition to be logged, and not disappear after the addition is complete, like the result with "html = html....".

hope this makes sense.

Sara Masek
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.a{fill-rule:evenodd;}techdegree
Sara Masek
Front End Web Development Techdegree Student 11,218 Points

hey Chun, it was kind of confusing to me too but I think what the html variable represents is just an initialized placeholder to hold the div elements; in other words, it's like an empty shell that has to be filled with a value (in this case the divs containing the value of "i").

Also, I think using "html" as a variable might have led to confusion. When I see html I immediately look at it as an object to manipulate the DOM rather than an empty variable, which is what this video set it to.

Hope that helps.