css/css-values/calc-unit-analysis.html

<!DOCTYPE HTML>
<html>
<head>
  <title>CSS Variables Allowed Syntax</title>
  <link rel="author" title="L. David Baron" href="https://dbaron.org/">
  <link rel="author" title="Mozilla Corporation" href="http://mozilla.com/" />
  <link rel="help" href="http://www.w3.org/TR/css3-values/#lengths" />
  <link rel="help" href="http://www.w3.org/TR/css3-values/#calc-type-checking" />
  <script src="/resources/testharness.js"></script>
  <script src="/resources/testharnessreport.js"></script>
<style id="style"></style>
<script id="metadata_cache">/*
{
  "unitless_zero_in_calc_is_a_numeric_type_not_length": { "assert": "invalid calc expression: unitless zero in calc() is a numeric type, not length" },
  "0px_in_calc": { "assert": "invalid calc expression: 0px in calc()" },
  "addition_of_length_and_number": { "assert": "invalid calc expression: addition of length and number" },
  "addition_of_number_and_length": { "assert": "invalid calc expression: addition of number and length" },
  "subtraction_of_length_and_number": { "assert": "invalid calc expression: subtraction of length and number" },
  "subtraction_of_number_and_length": { "assert": "invalid calc expression: subtraction of number and length" },
  "multiplication_of_length_and_number": { "assert": "invalid calc expression: multiplication of length and number" },
  "multiplication_of_number_and_length": { "assert": "invalid calc expression: multiplication of number and length" },
  "multiplication_of_length_and_length": { "assert": "invalid calc expression: multiplication of length and length" }
}
*/</script>
</head>
<body onload="run()">
<div id=log></div>
<div id="test"></div>
<script>

function run() {
  var test_elt = document.getElementById("test");
  var test_cs = window.getComputedStyle(test_elt, "");

  function description_to_name(description) {
    return description.replace(/\W+/g, "_").replace(/^_/, "").replace(/_$/, "");
  }

  function assert_invalid_value(property, value, description) {
    test(function() {
           test_elt.style.setProperty(property, "inherit");
           test_elt.style.setProperty(property, value);
           assert_equals(test_elt.style.getPropertyValue(property),
                         "inherit");
           test_elt.style.setProperty(property, value);
           test_elt.style.removeProperty(property);
         },
         description_to_name(description),
         { assert: "invalid calc expression: " + description });
  }

  function assert_valid_value(property, value, computes_to, description) {
    test(function() {
           test_elt.style.setProperty(property, "inherit");
           test_elt.style.setProperty(property, value);
           assert_not_equals(test_elt.style.getPropertyValue(property),
                             "inherit");
           assert_equals(test_cs.getPropertyValue(property),
                         computes_to);
           test_elt.style.removeProperty(property);
         },
         description_to_name(description),
         { assert: "valid calc expression: " + description });
  }

  assert_invalid_value("margin-left", "calc(0)",
                       "unitless zero in calc() is a numeric type, not length");
  assert_valid_value("margin-left", "calc(0px)", "0px",
                     "0px in calc()");
  assert_invalid_value("margin-left", "calc(1px + 2)",
                       "addition of length and number");
  assert_invalid_value("margin-left", "calc(2 + 1px)",
                       "addition of number and length");
  assert_invalid_value("margin-left", "calc(1px - 2)",
                       "subtraction of length and number");
  assert_invalid_value("margin-left", "calc(2 - 1px)",
                       "subtraction of number and length");
  assert_valid_value("margin-left", "calc(2px * 2)", "4px",
                     "multiplication of length and number");
  assert_valid_value("margin-left", "calc(2 * 2px)", "4px",
                     "multiplication of number and length");
  assert_invalid_value("margin-left", "calc(2px * 1px)",
                       "multiplication of length and length");

}

run();

</script>
</body>
</html>