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FAQ Topic - Why does 1+1 equal 11? or How do I convert a
string to a number?
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Variables are not typed; their values are. The conversion between a
string and a number happens automatically. Since plus (` + `) is
also used as in string concatenation, ` '1' + 1 ` is equal to ` '11' `.
The string determines what ` + ` does. To overcome this, first convert the
string to a number. For example: ` +varname ` or ` Number(varname) ` or
` parseInt(varname, 10) ` or ` parseFloat(varname) `.
Form control values are strings, as is the result from a ` prompt `
dialog. Convert these to numbers before performing addition by using
the unary ` + ` operator: ` +'1' + 1 ` result is ` 2 `.
Additional Notes:
http://www.jibbering.com/faq/faq_not...e_convert.html
http://msdn2.microsoft.com/en-us/library/67defydd.aspx
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