files/en-us/web/mathml/reference/element/msub/index.md
The <msub> MathML element is used to attach a subscript to an expression.
It uses the following syntax: <msub> base subscript </msub>.
This element's attributes include the global MathML attributes as well as the following deprecated attribute:
subscriptshift {{deprecated_inline}} {{Non-standard_Inline}}
[!NOTE] For the
subscriptshiftattribute, some browsers may also accept legacy MathML lengths.
<math display="block">
<msub>
<mi>X</mi>
<mn>1</mn>
</msub>
</math>
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