The video gave a history of Java, Javascript, and the process through which it became standardized. It seems that many companies played a part in the standardization and that because of this certain quirks and errors that are known problems still remain.
Some notes I took from this:
- JavaScript is loosely typed
- objects are dynamic, they are basically hash tables
- Prototypal inheritance: objects inherit directly from other objects, not classes
- Lambda functions are treated as 'first class' objects
- Linkage through global variables. This can cause many problems and is often a security risk. Need to learn to mitigate this problem.
- values:
- number
- string
- boolean
- object
- null
- undefined
- NaN is the result of undefined or broken operations
- NaN doesn't equal anything, not even NaN
- It's type is number.
- Javascript has a ton of unused reserved words.
- != and == can cause type coercion, use !== and === instead as they give exact equality.
- && and || are a bit different in js
- Bitwise operators are slow in js.
I also had to produce a bit of javascript that pops up an alert showing the results of 2 + 2.
The code is as follows:
<html>
<head>
<script type="text/javascript">
function message()
{
var x;
x = 2+2;
alert(x);
}
</script>
</head>
<body onload="message()">
</body>
</html>
It produced the following results:
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