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Javascript Numeric Validation

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Snippets Manager
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Jan. 29, 07 · · Code Snippet
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I've seen a lot of takes on numeric validation, and most have serious flaws. For example, (!isNaN) returns inconsistent results and shouldn't be used to verify numericality. This should cover all cases, and supports a decimal point as well as negative numbers.


function isNumeric(value) {
  if (value == null || !value.toString().match(/^[-]?\d*\.?\d*$/)) return false;
  return true;
}


This logic is straight-forward: if the parameter isn't null, convert it to a string and match it against a RegEx to throw out false cases. Otherwise, return true.
JavaScript

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