Get number of times regex .replace() occurs

I'm building an html linter, and first thing I am trying to do is remove all of the alt attributes. I'm using a regex to replace alt tags. Is there a way to get the number alt codes removed.

If you paste:

alt="23432" one two three alt='12312' four five six alt = "1124412"

You should get one two three four five six, and I would like to store 3 into a variable called numReplaced.

function removeAlts(input) {

	var textIn = document.getElementById("textIn").value;

	var regex = /alts*=s*["'][a-zA-z0-9s]*["']/ig;

	var textOut = textIn.replace(regex, '');

	document.getElementById("textIn").value = textOut;

  //var numReplaced = ????

}

<button class="btn" onclick="removeAlts()">Remove Alts</button>

<div class="title">

	<h3>Paste code in box below and press button to remove alts!</h3>

</div>

<textarea name="input" id="textIn" cols="60" rows=15"></textarea>

edited Nov 22 '18 at 5:23

asked Nov 22 '18 at 5:21

dvdktn

287

You need to take into account cases like alt="it's okay"

– Ahmad
Nov 22 '18 at 5:30

add a comment |

I'm building an html linter, and first thing I am trying to do is remove all of the alt attributes. I'm using a regex to replace alt tags. Is there a way to get the number alt codes removed.

If you paste:

alt="23432" one two three alt='12312' four five six alt = "1124412"

You should get one two three four five six, and I would like to store 3 into a variable called numReplaced.

function removeAlts(input) {

	var textIn = document.getElementById("textIn").value;

	var regex = /alts*=s*["'][a-zA-z0-9s]*["']/ig;

	var textOut = textIn.replace(regex, '');

	document.getElementById("textIn").value = textOut;

  //var numReplaced = ????

}

<button class="btn" onclick="removeAlts()">Remove Alts</button>

<div class="title">

	<h3>Paste code in box below and press button to remove alts!</h3>

</div>

<textarea name="input" id="textIn" cols="60" rows=15"></textarea>

edited Nov 22 '18 at 5:23

asked Nov 22 '18 at 5:21

dvdktn

287

You need to take into account cases like alt="it's okay"

– Ahmad
Nov 22 '18 at 5:30

add a comment |

I'm building an html linter, and first thing I am trying to do is remove all of the alt attributes. I'm using a regex to replace alt tags. Is there a way to get the number alt codes removed.

If you paste:

alt="23432" one two three alt='12312' four five six alt = "1124412"

You should get one two three four five six, and I would like to store 3 into a variable called numReplaced.

function removeAlts(input) {

	var textIn = document.getElementById("textIn").value;

	var regex = /alts*=s*["'][a-zA-z0-9s]*["']/ig;

	var textOut = textIn.replace(regex, '');

	document.getElementById("textIn").value = textOut;

  //var numReplaced = ????

}

<button class="btn" onclick="removeAlts()">Remove Alts</button>

<div class="title">

	<h3>Paste code in box below and press button to remove alts!</h3>

</div>

<textarea name="input" id="textIn" cols="60" rows=15"></textarea>

edited Nov 22 '18 at 5:23

asked Nov 22 '18 at 5:21

dvdktn

287

I'm building an html linter, and first thing I am trying to do is remove all of the alt attributes. I'm using a regex to replace alt tags. Is there a way to get the number alt codes removed.

If you paste:

alt="23432" one two three alt='12312' four five six alt = "1124412"

You should get one two three four five six, and I would like to store 3 into a variable called numReplaced.

function removeAlts(input) {

	var textIn = document.getElementById("textIn").value;

	var regex = /alts*=s*["'][a-zA-z0-9s]*["']/ig;

	var textOut = textIn.replace(regex, '');

	document.getElementById("textIn").value = textOut;

  //var numReplaced = ????

}

<button class="btn" onclick="removeAlts()">Remove Alts</button>

<div class="title">

	<h3>Paste code in box below and press button to remove alts!</h3>

</div>

<textarea name="input" id="textIn" cols="60" rows=15"></textarea>

function removeAlts(input) {

	var textIn = document.getElementById("textIn").value;

	var regex = /alts*=s*["'][a-zA-z0-9s]*["']/ig;

	var textOut = textIn.replace(regex, '');

	document.getElementById("textIn").value = textOut;

  //var numReplaced = ????

}

<button class="btn" onclick="removeAlts()">Remove Alts</button>

<div class="title">

	<h3>Paste code in box below and press button to remove alts!</h3>

</div>

<textarea name="input" id="textIn" cols="60" rows=15"></textarea>

function removeAlts(input) {

	var textIn = document.getElementById("textIn").value;

	var regex = /alts*=s*["'][a-zA-z0-9s]*["']/ig;

	var textOut = textIn.replace(regex, '');

	document.getElementById("textIn").value = textOut;

  //var numReplaced = ????

}

<button class="btn" onclick="removeAlts()">Remove Alts</button>

<div class="title">

	<h3>Paste code in box below and press button to remove alts!</h3>

</div>

<textarea name="input" id="textIn" cols="60" rows=15"></textarea>

javascript html regex

edited Nov 22 '18 at 5:23

asked Nov 22 '18 at 5:21

dvdktn

287

edited Nov 22 '18 at 5:23

asked Nov 22 '18 at 5:21

dvdktn

287

edited Nov 22 '18 at 5:23

asked Nov 22 '18 at 5:21

dvdktn

287

asked Nov 22 '18 at 5:21

dvdktn

287

asked Nov 22 '18 at 5:21

dvdktn

287

You need to take into account cases like alt="it's okay"

– Ahmad
Nov 22 '18 at 5:30

add a comment |

You need to take into account cases like alt="it's okay"

– Ahmad
Nov 22 '18 at 5:30

You need to take into account cases like alt="it's okay"

– Ahmad
Nov 22 '18 at 5:30

add a comment |

2 Answers
2

active

oldest

votes

One option would be to use a replacer function, and increment a counter every time it's called. You should also fix your regex to capture the initial double or single quote in the alt attribute, so that it can be matched later with a backreference. With this backreference strategy, you'll also be able to match alts with quotes in them, so add "' to the character set.

In addition, you can use the i flag instead of repeating [a-zA-Z, and d instead of 0-9. Also, quotes do not need to be escaped in regular expression literals.

function removeAlts(input) {

  var textIn = document.getElementById("textIn").value;

  var regex = /s*alts*=s*(["'])[a-zds"']*?1/ig;

  let counter = 0;

  var textOut = textIn.replace(regex, () => {

    counter++;

    return '';

  });

  document.getElementById("textIn").value = textOut;

  console.log(counter);

}

<button class="btn" onclick="removeAlts()">Remove Alts</button>

<div class="title">

  <h3>Paste code in box below and press button to remove alts!</h3>

</div>

<textarea name="input" id="textIn" cols="60" rows="15">

  <tag alt="foo"></tag>

  <tag alt="bar"></tag>

  <tag alt="that's okay"></tag>

</textarea>

But it would be far more elegant to use DOMParser to search for everything with an alt attribute, and remove them

function removeAlts(input) {

  var textIn = document.getElementById("textIn").value;

  const doc = new DOMParser().parseFromString(textIn, 'text/html');

  const alts = doc.querySelectorAll('[alt]');

  console.log(alts.length);

  alts.forEach(elm => elm.removeAttribute('alt'));

  document.getElementById("textIn").value = doc.body.innerHTML;

}

<button class="btn" onclick="removeAlts()">Remove Alts</button>

<div class="title">

  <h3>Paste code in box below and press button to remove alts!</h3>

</div>

<textarea name="input" id="textIn" cols="60" rows="15">

  <tag alt="foo"></tag>

  <tag alt="bar"></tag>

  <tag alt="that's okay"></tag>

</textarea>

edited Nov 22 '18 at 5:33

answered Nov 22 '18 at 5:23

CertainPerformance

87.3k154774

Your regex will not work properly in cases like alt="that's okay" since it contains double quotes and single quotes

– Ahmad
Nov 22 '18 at 5:26

Yep, need to fix OP's regex to capture that character and backreference it later

– CertainPerformance
Nov 22 '18 at 5:29

Thanks! I never knew about DOMParser :)

– dvdktn
Nov 22 '18 at 5:36

add a comment |

You may use same quote in the end of your pattern like this:
/alts*=s*(["']).+1/ig

answered Nov 22 '18 at 8:00

Technobulka

add a comment |

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2 Answers
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2 Answers
2

active

oldest

votes

In addition, you can use the i flag instead of repeating [a-zA-Z, and d instead of 0-9. Also, quotes do not need to be escaped in regular expression literals.

function removeAlts(input) {

  var textIn = document.getElementById("textIn").value;

  var regex = /s*alts*=s*(["'])[a-zds"']*?1/ig;

  let counter = 0;

  var textOut = textIn.replace(regex, () => {

    counter++;

    return '';

  });

  document.getElementById("textIn").value = textOut;

  console.log(counter);

}

<button class="btn" onclick="removeAlts()">Remove Alts</button>

<div class="title">

  <h3>Paste code in box below and press button to remove alts!</h3>

</div>

<textarea name="input" id="textIn" cols="60" rows="15">

  <tag alt="foo"></tag>

  <tag alt="bar"></tag>

  <tag alt="that's okay"></tag>

</textarea>

But it would be far more elegant to use DOMParser to search for everything with an alt attribute, and remove them

function removeAlts(input) {

  var textIn = document.getElementById("textIn").value;

  const doc = new DOMParser().parseFromString(textIn, 'text/html');

  const alts = doc.querySelectorAll('[alt]');

  console.log(alts.length);

  alts.forEach(elm => elm.removeAttribute('alt'));

  document.getElementById("textIn").value = doc.body.innerHTML;

}

<button class="btn" onclick="removeAlts()">Remove Alts</button>

<div class="title">

  <h3>Paste code in box below and press button to remove alts!</h3>

</div>

<textarea name="input" id="textIn" cols="60" rows="15">

  <tag alt="foo"></tag>

  <tag alt="bar"></tag>

  <tag alt="that's okay"></tag>

</textarea>

edited Nov 22 '18 at 5:33

answered Nov 22 '18 at 5:23

CertainPerformance

87.3k154774

Your regex will not work properly in cases like alt="that's okay" since it contains double quotes and single quotes

– Ahmad
Nov 22 '18 at 5:26

Yep, need to fix OP's regex to capture that character and backreference it later

– CertainPerformance
Nov 22 '18 at 5:29

Thanks! I never knew about DOMParser :)

– dvdktn
Nov 22 '18 at 5:36

add a comment |

In addition, you can use the i flag instead of repeating [a-zA-Z, and d instead of 0-9. Also, quotes do not need to be escaped in regular expression literals.

function removeAlts(input) {

  var textIn = document.getElementById("textIn").value;

  var regex = /s*alts*=s*(["'])[a-zds"']*?1/ig;

  let counter = 0;

  var textOut = textIn.replace(regex, () => {

    counter++;

    return '';

  });

  document.getElementById("textIn").value = textOut;

  console.log(counter);

}

<button class="btn" onclick="removeAlts()">Remove Alts</button>

<div class="title">

  <h3>Paste code in box below and press button to remove alts!</h3>

</div>

<textarea name="input" id="textIn" cols="60" rows="15">

  <tag alt="foo"></tag>

  <tag alt="bar"></tag>

  <tag alt="that's okay"></tag>

</textarea>

But it would be far more elegant to use DOMParser to search for everything with an alt attribute, and remove them

function removeAlts(input) {

  var textIn = document.getElementById("textIn").value;

  const doc = new DOMParser().parseFromString(textIn, 'text/html');

  const alts = doc.querySelectorAll('[alt]');

  console.log(alts.length);

  alts.forEach(elm => elm.removeAttribute('alt'));

  document.getElementById("textIn").value = doc.body.innerHTML;

}

<button class="btn" onclick="removeAlts()">Remove Alts</button>

<div class="title">

  <h3>Paste code in box below and press button to remove alts!</h3>

</div>

<textarea name="input" id="textIn" cols="60" rows="15">

  <tag alt="foo"></tag>

  <tag alt="bar"></tag>

  <tag alt="that's okay"></tag>

</textarea>

edited Nov 22 '18 at 5:33

answered Nov 22 '18 at 5:23

CertainPerformance

87.3k154774

Your regex will not work properly in cases like alt="that's okay" since it contains double quotes and single quotes

– Ahmad
Nov 22 '18 at 5:26

Yep, need to fix OP's regex to capture that character and backreference it later

– CertainPerformance
Nov 22 '18 at 5:29

Thanks! I never knew about DOMParser :)

– dvdktn
Nov 22 '18 at 5:36

add a comment |

In addition, you can use the i flag instead of repeating [a-zA-Z, and d instead of 0-9. Also, quotes do not need to be escaped in regular expression literals.

function removeAlts(input) {

  var textIn = document.getElementById("textIn").value;

  var regex = /s*alts*=s*(["'])[a-zds"']*?1/ig;

  let counter = 0;

  var textOut = textIn.replace(regex, () => {

    counter++;

    return '';

  });

  document.getElementById("textIn").value = textOut;

  console.log(counter);

}

<button class="btn" onclick="removeAlts()">Remove Alts</button>

<div class="title">

  <h3>Paste code in box below and press button to remove alts!</h3>

</div>

<textarea name="input" id="textIn" cols="60" rows="15">

  <tag alt="foo"></tag>

  <tag alt="bar"></tag>

  <tag alt="that's okay"></tag>

</textarea>

But it would be far more elegant to use DOMParser to search for everything with an alt attribute, and remove them

function removeAlts(input) {

  var textIn = document.getElementById("textIn").value;

  const doc = new DOMParser().parseFromString(textIn, 'text/html');

  const alts = doc.querySelectorAll('[alt]');

  console.log(alts.length);

  alts.forEach(elm => elm.removeAttribute('alt'));

  document.getElementById("textIn").value = doc.body.innerHTML;

}

<button class="btn" onclick="removeAlts()">Remove Alts</button>

<div class="title">

  <h3>Paste code in box below and press button to remove alts!</h3>

</div>

<textarea name="input" id="textIn" cols="60" rows="15">

  <tag alt="foo"></tag>

  <tag alt="bar"></tag>

  <tag alt="that's okay"></tag>

</textarea>

edited Nov 22 '18 at 5:33

answered Nov 22 '18 at 5:23

CertainPerformance

87.3k154774

In addition, you can use the i flag instead of repeating [a-zA-Z, and d instead of 0-9. Also, quotes do not need to be escaped in regular expression literals.

function removeAlts(input) {

  var textIn = document.getElementById("textIn").value;

  var regex = /s*alts*=s*(["'])[a-zds"']*?1/ig;

  let counter = 0;

  var textOut = textIn.replace(regex, () => {

    counter++;

    return '';

  });

  document.getElementById("textIn").value = textOut;

  console.log(counter);

}

<button class="btn" onclick="removeAlts()">Remove Alts</button>

<div class="title">

  <h3>Paste code in box below and press button to remove alts!</h3>

</div>

<textarea name="input" id="textIn" cols="60" rows="15">

  <tag alt="foo"></tag>

  <tag alt="bar"></tag>

  <tag alt="that's okay"></tag>

</textarea>

But it would be far more elegant to use DOMParser to search for everything with an alt attribute, and remove them

function removeAlts(input) {

  var textIn = document.getElementById("textIn").value;

  const doc = new DOMParser().parseFromString(textIn, 'text/html');

  const alts = doc.querySelectorAll('[alt]');

  console.log(alts.length);

  alts.forEach(elm => elm.removeAttribute('alt'));

  document.getElementById("textIn").value = doc.body.innerHTML;

}

<button class="btn" onclick="removeAlts()">Remove Alts</button>

<div class="title">

  <h3>Paste code in box below and press button to remove alts!</h3>

</div>

<textarea name="input" id="textIn" cols="60" rows="15">

  <tag alt="foo"></tag>

  <tag alt="bar"></tag>

  <tag alt="that's okay"></tag>

</textarea>

function removeAlts(input) {

  var textIn = document.getElementById("textIn").value;

  var regex = /s*alts*=s*(["'])[a-zds"']*?1/ig;

  let counter = 0;

  var textOut = textIn.replace(regex, () => {

    counter++;

    return '';

  });

  document.getElementById("textIn").value = textOut;

  console.log(counter);

}

<button class="btn" onclick="removeAlts()">Remove Alts</button>

<div class="title">

  <h3>Paste code in box below and press button to remove alts!</h3>

</div>

<textarea name="input" id="textIn" cols="60" rows="15">

  <tag alt="foo"></tag>

  <tag alt="bar"></tag>

  <tag alt="that's okay"></tag>

</textarea>

function removeAlts(input) {

  var textIn = document.getElementById("textIn").value;

  var regex = /s*alts*=s*(["'])[a-zds"']*?1/ig;

  let counter = 0;

  var textOut = textIn.replace(regex, () => {

    counter++;

    return '';

  });

  document.getElementById("textIn").value = textOut;

  console.log(counter);

}

<button class="btn" onclick="removeAlts()">Remove Alts</button>

<div class="title">

  <h3>Paste code in box below and press button to remove alts!</h3>

</div>

<textarea name="input" id="textIn" cols="60" rows="15">

  <tag alt="foo"></tag>

  <tag alt="bar"></tag>

  <tag alt="that's okay"></tag>

</textarea>

function removeAlts(input) {

  var textIn = document.getElementById("textIn").value;

  const doc = new DOMParser().parseFromString(textIn, 'text/html');

  const alts = doc.querySelectorAll('[alt]');

  console.log(alts.length);

  alts.forEach(elm => elm.removeAttribute('alt'));

  document.getElementById("textIn").value = doc.body.innerHTML;

}

<button class="btn" onclick="removeAlts()">Remove Alts</button>

<div class="title">

  <h3>Paste code in box below and press button to remove alts!</h3>

</div>

<textarea name="input" id="textIn" cols="60" rows="15">

  <tag alt="foo"></tag>

  <tag alt="bar"></tag>

  <tag alt="that's okay"></tag>

</textarea>

function removeAlts(input) {

  var textIn = document.getElementById("textIn").value;

  const doc = new DOMParser().parseFromString(textIn, 'text/html');

  const alts = doc.querySelectorAll('[alt]');

  console.log(alts.length);

  alts.forEach(elm => elm.removeAttribute('alt'));

  document.getElementById("textIn").value = doc.body.innerHTML;

}

<button class="btn" onclick="removeAlts()">Remove Alts</button>

<div class="title">

  <h3>Paste code in box below and press button to remove alts!</h3>

</div>

<textarea name="input" id="textIn" cols="60" rows="15">

  <tag alt="foo"></tag>

  <tag alt="bar"></tag>

  <tag alt="that's okay"></tag>

</textarea>

edited Nov 22 '18 at 5:33

answered Nov 22 '18 at 5:23

CertainPerformance

87.3k154774

edited Nov 22 '18 at 5:33

answered Nov 22 '18 at 5:23

CertainPerformance

87.3k154774

answered Nov 22 '18 at 5:23

CertainPerformance

87.3k154774

answered Nov 22 '18 at 5:23

CertainPerformance

87.3k154774

Your regex will not work properly in cases like alt="that's okay" since it contains double quotes and single quotes

– Ahmad
Nov 22 '18 at 5:26

Yep, need to fix OP's regex to capture that character and backreference it later

– CertainPerformance
Nov 22 '18 at 5:29

Thanks! I never knew about DOMParser :)

– dvdktn
Nov 22 '18 at 5:36

add a comment |

Your regex will not work properly in cases like alt="that's okay" since it contains double quotes and single quotes

– Ahmad
Nov 22 '18 at 5:26

Yep, need to fix OP's regex to capture that character and backreference it later

– CertainPerformance
Nov 22 '18 at 5:29

Thanks! I never knew about DOMParser :)

– dvdktn
Nov 22 '18 at 5:36

Your regex will not work properly in cases like alt="that's okay" since it contains double quotes and single quotes

– Ahmad
Nov 22 '18 at 5:26

Yep, need to fix OP's regex to capture that character and backreference it later

– CertainPerformance
Nov 22 '18 at 5:29

Thanks! I never knew about DOMParser :)

– dvdktn
Nov 22 '18 at 5:36

add a comment |

You may use same quote in the end of your pattern like this:
/alts*=s*(["']).+1/ig

answered Nov 22 '18 at 8:00

Technobulka

add a comment |

You may use same quote in the end of your pattern like this:
/alts*=s*(["']).+1/ig

answered Nov 22 '18 at 8:00

Technobulka

add a comment |

You may use same quote in the end of your pattern like this:
/alts*=s*(["']).+1/ig

answered Nov 22 '18 at 8:00

Technobulka

You may use same quote in the end of your pattern like this:
/alts*=s*(["']).+1/ig

answered Nov 22 '18 at 8:00

Technobulka

answered Nov 22 '18 at 8:00

Technobulka

answered Nov 22 '18 at 8:00

Technobulka

answered Nov 22 '18 at 8:00

Technobulka

add a comment |

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