If you're sure that the string will always be something like "100*100" you could eval()
it, although most people will tell you this isn't a good idea on account of the fact that people could pass in malicious code to be eval'd.
eval("100*100");
>> 10000
Otherwise, you'll have to find or write a custom equation parser. In that case, you might want to take a look at the Shunting-yard algorithm, and read up on parsing.
Using split()
:
var myEquation = "100*100";
var num = myEquation.split("*")[0] * myEquation.split("*")[1];
>> 10000
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