| 2. 1. 7. Subtraction (-) |
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The subtraction operator (-) subtracts the number to the right of the operator from the number on the left. |
When either of the operands are strings, an attempt is made to convert the strings to numbers. |
For example, the line of code: |
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var resultOfSub = 25 - 102;
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would result in the value -77 being stored in the variable resultOfSub. |
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<html>
<script language="JavaScript">
<!--
aString = new String("45");
answer = aString - 25;
document.write("answer = (45-25)<br>");
document.write("answer = ",answer);
-->
</script>
</html>
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The subtract operator has special rules to deal with the variety of type conversions present in JavaScript: |
- If the two operands are numbers, perform arithmetic subtract and return the result.
- If either number is NaN, the result is NaN.
- If Infinity is subtracted from Infinity, the result is NaN.
- If –Infinity is subtracted from –Infinity, the result is NaN.
- If –Infinity is subtracted from Infinity, the result is Infinity.
- If Infinity is subtracted from –Infinity, the result is –Infinity.
- If +0 is subtracted from +0, the result is +0.
- If –0 is subtracted from +0, the result is –0.
- If –0 is subtracted from –0, the result is +0.
- If either of the two operands is not a number, the result is NaN.
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