The emoji characters render differently on different platforms: see the
comparison chart.
This depends on the operating system and the font used by the browser.
Here is a comparison of Pizza slice character on the Chrome browser:
Mac:
Windows 7:
Chrome OS: ![Chrome/Chrome OD](https://cdn.statically.io/img/i.sstatic.net/r63QN.png)
And this is the character itself, rendered by the browser you are
now using.
🍕
Google did not accept this ambiguity. Their solution was to use
an SVG font (apparently, their own).
For example, this is their rendering of the pizza slice,
as an extremely long sequence that draws the emoji:
<path fill="#333333" d="m108.990036 308.3322q0 0.96875 -0.25 2.203125q-0.09375 0.453125 -0.359375 0.75q-0.25 0.28125 -0.640625 0.5q-0.375 0.21875 -2.71875 1.078125q-2.34375 0.859375 -7.140625 2.4375l-0.953125 0.3125q-1.859375 0.59375 -2.40625 1.6875q-0.703125 1.28125 -2.125 1.28125q-0.453125 0 -0.828125 -0.15625q-0.375 -0.15625 -0.703125 -0.328125q-0.328125 -0.171875 -0.640625 -0.328125q-0.3125 -0.15625 -0.640625 -0.15625q-0.625 0 -1.015625 0.546875q-0.84375 1.125 -2.3125 1.125q-0.453125 0 -1.046875 -0.234375q-0.609375 -0.21875 -0.828125 -0.21875q-0.484375 0 -0.796875 0.515625q-0.296875 0.5 -0.359375 1.265625q-0.109375 0.875 -0.75 1.46875q-0.625 0.59375 -1.40625 0.59375q-1.4375 0 -2.125 -1.890625q-0.6875 -1.90625 -0.6875 -3.75q0 -2.34375 1.328125 -4.75q1.34375 -2.40625 4.78125 -6.78125l3.890625 -5.0q0.265625 -0.375 0.609375 -0.828125q0.34375 -0.453125 0.375 -0.9375q0.21875 -2.140625 1.34375 -3.3125q1.125 -1.171875 2.953125 -1.171875q0.90625 0 2.125 0.296875q1.21875 0.296875 2.078125 0.640625q4.890625 1.8125 8.0625 5.421875q3.1875 3.609375 3.1875 7.71875zm-16.59375 8.84375q0.59375 0 0.875 -0.53125q0.3125 -0.59375 0.765625 -1.015625q0.46875 -0.4375 1.0 -0.71875q0.53125 -0.296875 1.90625 -0.765625q2.5625 -0.828125 4.40625 -1.453125q1.859375 -0.625 3.765625 -1.34375q1.90625 -0.71875 2.078125 -0.859375q0.171875 -0.140625 0.171875 -0.265625q0.234375 -1.125 0.234375 -1.796875l-0.03125 -0.890625q-0.234375 -0.59375 -0.578125 -0.953125q-0.328125 -0.359375 -0.953125 -0.359375q-1.09375 0 -1.640625 0.625q-0.546875 0.609375 -0.546875 1.59375q0 1.28125 -1.109375 1.828125q-1.265625 0.484375 -2.5 0.703125q-1.1875 0.234375 -1.65625 0.40625q-1.375 0.53125 -2.796875 0.96875l-11.0 3.59375q-0.875 0.28125 -1.75 0.484375q-0.859375 0.203125 -1.46875 0.53125q-0.15625 0.109375 -0.296875 0.109375q-0.203125 0 -0.375 -0.15625q-0.171875 -0.15625 -0.171875 -0.421875q0 -0.703125 2.0625 -1.171875q2.515625 -0.65625 4.9375 -1.5l4.921875 -1.625q4.375 -1.421875 5.53125 -1.875q0.578125 -0.234375 1.140625 -0.3125q1.15625 -0.15625 2.09375 -0.453125q0.9375 -0.296875 1.09375 -0.453125q-0.1875 -0.859375 -0.484375 -1.59375q-0.390625 0.65625 -1.203125 1.046875q-0.8125 0.390625 -1.6875 0.390625q-1.15625 0 -1.921875 -0.59375q-0.75 -0.609375 -0.75 -1.5625l0 -0.265625l0.015625 -0.21875q0.03125 -0.4375 0.421875 -0.953125q0.390625 -0.515625 0.984375 -0.859375q0.609375 -0.34375 1.265625 -0.34375q0.515625 0 1.078125 0.15625q-1.46875 -1.84375 -3.15625 -2.796875q-1.671875 -0.96875 -3.78125 -1.234375q0.5625 0.5625 0.5625 1.453125q0 0.9375 -1.0 1.78125q-1.0 0.828125 -2.25 0.828125q-0.90625 0 -1.578125 -0.375q-0.671875 -0.390625 -0.828125 -1.09375q-1.40625 1.875 -3.09375 3.921875q1.203125 0 2.046875 0.65625q0.84375 0.65625 0.84375 1.625q0 1.0625 -0.96875 1.78125q-0.953125 0.71875 -2.15625 0.71875q-0.65625 0 -1.34375 -0.265625q-0.6875 -0.28125 -1.09375 -0.84375q-1.796875 2.71875 -2.296875 4.015625q-0.5 1.296875 -0.5 2.5625q0 1.359375 0.453125 2.796875q0.46875 1.421875 0.984375 1.421875q0.25 0 0.453125 -0.234375q0.21875 -0.234375 0.328125 -0.578125q0.25 -1.421875 0.890625 -2.21875q0.640625 -0.796875 1.640625 -0.796875q0.453125 0 1.546875 0.390625l0.328125 0.078125q0.828125 0 1.171875 -0.578125q0.828125 -1.109375 2.15625 -1.109375q0.46875 0 0.828125 0.15625q0.359375 0.15625 0.671875 0.328125q0.328125 0.171875 0.640625 0.328125q0.3125 0.15625 0.671875 0.15625zm1.140625 -21.546875q-1.21875 0 -1.984375 0.8125q-0.765625 0.796875 -0.921875 2.421875l1.78125 0.125q2.734375 0.390625 4.21875 1.03125q1.484375 0.640625 2.703125 1.71875q1.234375 1.0625 2.15625 2.390625q0.9375 1.328125 1.53125 2.8125q0.390625 -0.859375 1.125 -1.34375q0.75 -0.484375 1.625 -0.484375q0.859375 0 1.265625 0.171875q-0.609375 -1.65625 -1.96875 -3.359375q-1.34375 -1.703125 -3.34375 -3.09375q-1.984375 -1.40625 -4.34375 -2.296875q-2.359375 -0.90625 -3.84375 -0.90625zm-4.734375 14.21875q0 -0.984375 0.75 -1.53125l0.578125 -0.359375q-0.1875 -0.390625 -0.1875 -0.765625q0 -0.734375 0.609375 -1.203125q0.625 -0.484375 1.53125 -0.484375q1.609375 0 1.90625 1.25l0.453125 -0.0625q0.796875 0 1.375 0.59375q0.578125 0.578125 0.578125 1.4375q0 0.859375 -0.640625 1.390625q-0.625 0.515625 -1.609375 0.515625q-0.53125 0 -1.03125 -0.125q-0.84375 1.328125 -2.3125 1.328125q-0.859375 0 -1.421875 -0.546875q-0.546875 -0.546875 -0.578125 -1.4375zm1.75 -0.828125q-0.640625 0.28125 -0.640625 0.796875q0 0.421875 0.28125 0.65625q0.28125 0.234375 0.609375 0.234375q0.828125 0 1.359375 -0.78125q0.28125 -0.65625 0.828125 -0.65625q0.28125 0 0.609375 0.21875q0.84375 0 1.25 -0.109375q0.40625 -0.109375 0.40625 -0.65625q0 -0.375 -0.21875 -0.640625q-0.203125 -0.28125 -0.59375 -0.28125l-0.359375 0.078125q-0.203125 0.21875 -0.640625 0.21875q-0.25 0 -0.421875 -0.203125q-0.15625 -0.203125 -0.15625 -0.5l0.03125 -0.328125q0 -0.453125 -0.8125 -0.453125q-0.546875 0 -0.78125 0.21875q-0.234375 0.203125 -0.234375 0.359375q0 0.234375 0.09375 0.390625q0.46875 0.109375 0.46875 0.78125q0 0.3125 -0.203125 0.5q-0.203125 0.1875 -0.546875 0.1875l-0.328125 -0.03125z" fill-rule="nonzero"></path>
The result is: ![Presentation mode](https://cdn.statically.io/img/i.sstatic.net/1M51S.png)
This succeeds in making the emojis platform-independent, so they will
display identically on all platforms, but at the cost of losing the colors.
My own opinion that the inventor of the SVG method just missed out
on the whole idea of emojis.
Google has not implemented this "solution" in their phone software,
so the emojis created there have colors, but they will be displayed
differently on different platforms, as you can see in the above
comparison chart.
There is no way to fix this behavior in the desktop, except for
using another browser than Chrome. You may also use small
images instead of emoji sequences in some cases.
(source)