This test striking through the first 21st letters. Every letter including spaces before "jumps" must be striked.

"The quick brown fox jumps over the lazy dog" uses every letter in the english language.
execStrikethroughCommand: <span id="test"><strike>"</strike>The quick brown fox jumps over the lazy dog" uses every letter in the english language. </span>
execStrikethroughCommand: <span id="test">"The quick brown fox jumps over the lazy dog" uses every letter in the english language. </span>
execStrikethroughCommand: <span id="test"><strike>"Th</strike>e quick brown fox jumps over the lazy dog" uses every letter in the english language. </span>
execStrikethroughCommand: <span id="test">"The quick brown fox jumps over the lazy dog" uses every letter in the english language. </span>
execStrikethroughCommand: <span id="test"><strike>"The </strike>quick brown fox jumps over the lazy dog" uses every letter in the english language. </span>
execStrikethroughCommand: <span id="test">"The quick brown fox jumps over the lazy dog" uses every letter in the english language. </span>
execStrikethroughCommand: <span id="test"><strike>"The qu</strike>ick brown fox jumps over the lazy dog" uses every letter in the english language. </span>
execStrikethroughCommand: <span id="test">"The quick brown fox jumps over the lazy dog" uses every letter in the english language. </span>
execStrikethroughCommand: <span id="test"><strike>"The quic</strike>k brown fox jumps over the lazy dog" uses every letter in the english language. </span>
execStrikethroughCommand: <span id="test">"The quick brown fox jumps over the lazy dog" uses every letter in the english language. </span>
execStrikethroughCommand: <span id="test"><strike>"The quick </strike>brown fox jumps over the lazy dog" uses every letter in the english language. </span>
execStrikethroughCommand: <span id="test">"The quick brown fox jumps over the lazy dog" uses every letter in the english language. </span>
execStrikethroughCommand: <span id="test"><strike>"The quick br</strike>own fox jumps over the lazy dog" uses every letter in the english language. </span>
execStrikethroughCommand: <span id="test">"The quick brown fox jumps over the lazy dog" uses every letter in the english language. </span>
execStrikethroughCommand: <span id="test"><strike>"The quick brow</strike>n fox jumps over the lazy dog" uses every letter in the english language. </span>
execStrikethroughCommand: <span id="test">"The quick brown fox jumps over the lazy dog" uses every letter in the english language. </span>
execStrikethroughCommand: <span id="test"><strike>"The quick brown </strike>fox jumps over the lazy dog" uses every letter in the english language. </span>
execStrikethroughCommand: <span id="test">"The quick brown fox jumps over the lazy dog" uses every letter in the english language. </span>
execStrikethroughCommand: <span id="test"><strike>"The quick brown fo</strike>x jumps over the lazy dog" uses every letter in the english language. </span>
execStrikethroughCommand: <span id="test">"The quick brown fox jumps over the lazy dog" uses every letter in the english language. </span>
execStrikethroughCommand: <span id="test"><strike>"The quick brown fox </strike>jumps over the lazy dog" uses every letter in the english language. </span>