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What is negative infinity?
It’s a number in JavaScript, derived by dividing negative number by zero.
What boolean operators does JavaScript support?
&&, || and !
What does "1"+2+4 evaluate to?
Since 1 is a string, everything is a string, so the result is 124.
How about 2+5+"8"?
Since 2 and 5 are integers, this is number arithmetic, since 8 is a string, it’s concatenation, so 78 is the result.
What looping structures are there in JavaScript?
for, while, do-while loops, but no foreach.
How do you create a new object in JavaScript?
var obj = new Object(); or var obj = {};
How do you assign object properties?
obj["age"] = 17 or obj.age = 17.
What’s a way to append a value to an array?
arr[arr.length] = value;
What is this keyword?
It refers to the current object.
.How can JavaScript make a Web site easier to use? That is, are there certain JavaScript techniques that make it easier for people to use a Web site?
JavaScript's greatest potential gift to a Web site is that scripts can make the page more immediately interactive, that is, interactive without having to submit every little thing to the server for a server program to re-render the page and send it back to the client. For example, consider a top-level navigation panel that has, say, six primary image map links into subsections of the Web site. With only a little bit of scripting, each map area can be instructed to pop up a more detailed list of links to the contents within a subsection whenever the user rolls the cursor atop a map area. With the help of that popup list of links, the user with a scriptable browser can bypass one intermediate menu page. The user without a scriptable browser (or who has disabled JavaScript) will have to drill down through a more traditiona/javal and time-consuming path to the desired content.
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