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JavaScript only has one simple type, namely:
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var anumber = 137; // use var to define a number
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var astring = "1"; // or to define a string
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Loose typing in JavaScript allows interpreter to creatively interpret an expression. Note that strings take precedence over numbers:
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var x = astring + anumber; // results in x = "1137"
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(Early versions of JS inferred the type from the leftmost variable.)
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Use parseInt and parseFloat to extract numerical values from strings
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Note special value null (no quotes) can be used as a null value
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Strings can be delimited by '..text..' or "..text.." which are identical in meaning (unlike PERL). Also, one can use \n for newline and \t for tab (and a few others).
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Boolean literals are either true or false
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Comments come in two flavors:
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/* any text including newlines */
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statements; // comment terminated by newline
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