mteb/BrightProStackoverflowRetrieval huggingface dataset:
[ ](https://kotlinlang.org) [ v1.9.23
](https://github.com/JetBrains/kotlin/releases/tag/v1.9.23)

  * Solutions 
    * [ Multiplatform ](/lp/mobile/)
    * [ Server-side ](/lp/server-side/)
    * [ Data science ](/docs/data-science-overview.html)
    * [ Android ](/docs/android-overview.html)
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  * [ Teach ](/education/)
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    * [ Koans ](https://play.kotlinlang.org/koans)

[ â Docs ](/docs/home.html)

[ kotlin-stdlib ](../../index.html) / [ kotlin.properties ](../index.html) / [
ObservableProperty ](index.html) / [ beforeChange ](./before-change.html)

#  beforeChange

Common

JVM

JS

Native

1.0

` protected  open  fun  beforeChange  (  
Â Â Â Â  property  :  Â [ KProperty
](../../kotlin.reflect/-k-property/index.html) < *  > ,  
Â Â Â Â  oldValue  :  Â  V  ,  
Â Â Â Â  newValue  :  Â  V  
)  :  Boolean  `  
[ (source)
](https://github.com/JetBrains/kotlin/tree/0938b46726b9c6938df309098316ce741815bb55/libraries/stdlib/src/kotlin/properties/ObservableProperty.kt#L23)

The callback which is called before a change to the property value is
attempted. The value of the property hasn't been changed yet, when this
callback is invoked. If the callback returns ` true ` the value of the
property is being set to the new value, and if the callback returns ` false `
the new value is discarded and the property remains its old value.

Stay in touch:

[ ](https://github.com/JetBrains/kotlin "Kotlin on GitHub") [
](https://twitter.com/kotlin "Kotlin on Twitter") [
](https://surveys.jetbrains.com/s3/kotlin-slack-sign-up "Kotlin Slack") [
](https://www.reddit.com/r/Kotlin/ "Kotlin on Reddit") [
](https://stackoverflow.com/questions/tagged/kotlin "Kotlin on Stack
Overflow") [ ](https://www.youtube.com/channel/UCP7uiEZIqci43m22KDl0sNw
"Kotlin on YouTube")

  * [ Contributing to Kotlin ](https://kotlinlang.org/docs/contribute.html "Contributing to Kotlin")
  * [ Releases ](https://kotlinlang.org/docs/releases.html "Releases")
  * [ Press Kit ](https://kotlinlang.org/assets/kotlin-media-kit.pdf "Press Kit")
  * [ Security ](https://kotlinlang.org/docs/security.html "Security")
  * [ Blog ](https://blog.jetbrains.com/kotlin/ "Blog")
  * [ Issue Tracker ](https://youtrack.jetbrains.com/issues/KT "Issue Tracker")
  * [ Brand assets ](https://resources.jetbrains.com/storage/products/kotlin/docs/kotlin_logos.zip "Brand assets")
  * [ Careers ](https://www.jetbrains.com/careers/jobs/?team=Kotlin "Careers")

[ ](https://jetbrains.com)

Supported and developed byÂ [ JetBrains ](https://www.jetbrains.com/) .

Kotlinâ¢ isÂ protected under the  [ KotlinÂ Foundation
](https://kotlinlang.org/foundation/kotlin-foundation.html)  
andÂ licensed under the  [ Apache 2Â license
](https://github.com/JetBrains/kotlin-web-site/blob/master/LICENSE) .
[ ](https://kotlinlang.org) [ v1.9.23
](https://github.com/JetBrains/kotlin/releases/tag/v1.9.23)

  * Solutions 
    * [ Multiplatform ](/lp/mobile/)
    * [ Server-side ](/lp/server-side/)
    * [ Data science ](/docs/data-science-overview.html)
    * [ Android ](/docs/android-overview.html)
  * [ Docs ](/docs/home.html)
  * [ Community ](/community/)
  * [ Teach ](/education/)
  * Play 
    * [ Playground ](https://play.kotlinlang.org/)
    * [ Examples ](https://play.kotlinlang.org/byExample)
    * [ Koans ](https://play.kotlinlang.org/koans)

[ â Docs ](/docs/home.html)

[ kotlin-stdlib ](../../index.html) / [ kotlin.properties ](../index.html) / [
ObservableProperty ](index.html) / [ getValue ](./get-value.html)

#  getValue

Common

JVM

JS

Native

1.0

` open  fun  getValue  (  thisRef  :  Â  Any  ?  ,  property  :  Â [ KProperty
](../../kotlin.reflect/-k-property/index.html) < *  > )  :  V  `  
[ (source)
](https://github.com/JetBrains/kotlin/tree/0938b46726b9c6938df309098316ce741815bb55/libraries/stdlib/src/kotlin/properties/ObservableProperty.kt#L31)

Returns the value of the property for the given object.

###  Parameters

` thisRef ` \- the object for which the value is requested.

` property ` \- the metadata for the property.

**Return** the property value.

Stay in touch:

[ ](https://github.com/JetBrains/kotlin "Kotlin on GitHub") [
](https://twitter.com/kotlin "Kotlin on Twitter") [
](https://surveys.jetbrains.com/s3/kotlin-slack-sign-up "Kotlin Slack") [
](https://www.reddit.com/r/Kotlin/ "Kotlin on Reddit") [
](https://stackoverflow.com/questions/tagged/kotlin "Kotlin on Stack
Overflow") [ ](https://www.youtube.com/channel/UCP7uiEZIqci43m22KDl0sNw
"Kotlin on YouTube")

  * [ Contributing to Kotlin ](https://kotlinlang.org/docs/contribute.html "Contributing to Kotlin")
  * [ Releases ](https://kotlinlang.org/docs/releases.html "Releases")
  * [ Press Kit ](https://kotlinlang.org/assets/kotlin-media-kit.pdf "Press Kit")
  * [ Security ](https://kotlinlang.org/docs/security.html "Security")
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  * [ Brand assets ](https://resources.jetbrains.com/storage/products/kotlin/docs/kotlin_logos.zip "Brand assets")
  * [ Careers ](https://www.jetbrains.com/careers/jobs/?team=Kotlin "Careers")

[ ](https://jetbrains.com)

Supported and developed byÂ [ JetBrains ](https://www.jetbrains.com/) .

Kotlinâ¢ isÂ protected under the  [ KotlinÂ Foundation
](https://kotlinlang.org/foundation/kotlin-foundation.html)  
andÂ licensed under the  [ Apache 2Â license
](https://github.com/JetBrains/kotlin-web-site/blob/master/LICENSE) .
[ ](https://kotlinlang.org) [ v1.9.23
](https://github.com/JetBrains/kotlin/releases/tag/v1.9.23)

  * Solutions 
    * [ Multiplatform ](/lp/mobile/)
    * [ Server-side ](/lp/server-side/)
    * [ Data science ](/docs/data-science-overview.html)
    * [ Android ](/docs/android-overview.html)
  * [ Docs ](/docs/home.html)
  * [ Community ](/community/)
  * [ Teach ](/education/)
  * Play 
    * [ Playground ](https://play.kotlinlang.org/)
    * [ Examples ](https://play.kotlinlang.org/byExample)
    * [ Koans ](https://play.kotlinlang.org/koans)

[ â Docs ](/docs/home.html)

[ kotlin-stdlib ](../../index.html) / [ kotlin.properties ](../index.html) / [
ObservableProperty ](index.html) / [ afterChange ](./after-change.html)

#  afterChange

Common

JVM

JS

Native

1.0

` protected  open  fun  afterChange  (  
Â Â Â Â  property  :  Â [ KProperty
](../../kotlin.reflect/-k-property/index.html) < *  > ,  
Â Â Â Â  oldValue  :  Â  V  ,  
Â Â Â Â  newValue  :  Â  V  )  `  
[ (source)
](https://github.com/JetBrains/kotlin/tree/0938b46726b9c6938df309098316ce741815bb55/libraries/stdlib/src/kotlin/properties/ObservableProperty.kt#L29)

The callback which is called after the change of the property is made. The
value of the property has already been changed when this callback is invoked.

Stay in touch:

[ ](https://github.com/JetBrains/kotlin "Kotlin on GitHub") [
](https://twitter.com/kotlin "Kotlin on Twitter") [
](https://surveys.jetbrains.com/s3/kotlin-slack-sign-up "Kotlin Slack") [
](https://www.reddit.com/r/Kotlin/ "Kotlin on Reddit") [
](https://stackoverflow.com/questions/tagged/kotlin "Kotlin on Stack
Overflow") [ ](https://www.youtube.com/channel/UCP7uiEZIqci43m22KDl0sNw
"Kotlin on YouTube")

  * [ Contributing to Kotlin ](https://kotlinlang.org/docs/contribute.html "Contributing to Kotlin")
  * [ Releases ](https://kotlinlang.org/docs/releases.html "Releases")
  * [ Press Kit ](https://kotlinlang.org/assets/kotlin-media-kit.pdf "Press Kit")
  * [ Security ](https://kotlinlang.org/docs/security.html "Security")
  * [ Blog ](https://blog.jetbrains.com/kotlin/ "Blog")
  * [ Issue Tracker ](https://youtrack.jetbrains.com/issues/KT "Issue Tracker")
  * [ Brand assets ](https://resources.jetbrains.com/storage/products/kotlin/docs/kotlin_logos.zip "Brand assets")
  * [ Careers ](https://www.jetbrains.com/careers/jobs/?team=Kotlin "Careers")

[ ](https://jetbrains.com)

Supported and developed byÂ [ JetBrains ](https://www.jetbrains.com/) .

Kotlinâ¢ isÂ protected under the  [ KotlinÂ Foundation
](https://kotlinlang.org/foundation/kotlin-foundation.html)  
andÂ licensed under the  [ Apache 2Â license
](https://github.com/JetBrains/kotlin-web-site/blob/master/LICENSE) .
1  2  3  4  5  6  7  8  9  10  11  12  13  14  15  16  17  18  19  20  21  22  23  24  25  26  27  28  29  30  31  32  33  34  35  | 
    
    
    <!doctype html><html lang="en"><head>  <meta charset="utf-8">  <title>css demo</title>  <style>  p {    color: blue;    font-weight: bold;    cursor: pointer;  }  </style>  <script src="https://code.jquery.com/jquery-3.7.0.js"></script></head><body> <p>  Once upon a time there was a man  who lived in a pizza parlor. This  man just loved pizza and ate it all  the time.  He went on to be the  happiest man in the world.  The end.</p> <script>var words = $( "p" ).first().text().split( /\s+/ );var text = words.join( "</span> <span>" );$( "p" ).first().html( "<span>" + text + "</span>" );$( "span" ).on( "click", function() {  $( this ).css( "background-color", "yellow" );});</script> </body></html>  
  
---|---  
  
####  Demo:

Change the font weight and background color on mouseenter and mouseleave.
1  2  3  4  5  6  7  8  9  10  11  12  13  14  15  16  17  18  19  20  21  22  23  24  25  26  27  28  | 
    
    
    <!doctype html><html lang="en"><head>  <meta charset="utf-8">  <title>css demo</title>  <style>  p {    color: blue;    width: 200px;    font-size: 14px;  }  </style>  <script src="https://code.jquery.com/jquery-3.7.0.js"></script></head><body>   <p>Just roll the mouse over me.</p>   <p>Or me to see a color change.</p> <script>$( "p" ).on( "mouseover", function() {  $( this ).css( "color", "red" );});</script> </body></html>  
  
---|---  
  
####  Demo:

Increase the width of #box by 200 pixels the first time it is clicked.
1  2  3  4  5  6  7  8  9  10  11  12  13  14  15  16  17  18  19  20  21  22  23  24  25  26  27  28  29  30  31  32  33  34  35  36  37  38  39  40  41  42  43  44  45  46  47  48  49  50  51  52  53  54  55  56  57  58  59  | 
    
    
    <!doctype html><html lang="en"><head>  <meta charset="utf-8">  <title>css demo</title>  <style>  div {    height: 50px;    margin: 5px;    padding: 5px;    float: left;  }  #box1 {    width: 50px;    color: yellow;    background-color: blue;  }  #box2 {    width: 80px;    color: rgb(255, 255, 255);    background-color: rgb(15, 99, 30);  }  #box3 {    width: 40px;    color: #fcc;    background-color: #123456;  }  #box4 {    width: 70px;    background-color: #f11;  }  </style>  <script src="https://code.jquery.com/jquery-3.7.0.js"></script></head><body> <p id="result">&nbsp;</p><div id="box1">1</div><div id="box2">2</div><div id="box3">3</div><div id="box4">4</div> <script>$( "div" ).on( "click", function() {  var html = [ "The clicked div has the following styles:" ];   var styleProps = $( this ).css([    "width", "height", "color", "background-color"  ]);  $.each( styleProps, function( prop, value ) {    html.push( prop + ": " + value );  });   $( "#result" ).html( html.join( "<br>" ) );});</script> </body></html>  
  
---|---  
  
####  Demo:

##  .css( propertyName, value )  Returns:  jQuery
FJavaScript%2FReference%2FGlobal_Objects%2FObject%2FObject%0A*+GitHub+URL%3A+https%3A%2F%2Fgithub.com%2Fmdn%2Fcontent%2Fblob%2Fmain%2Ffiles%2Fen-
us%2Fweb%2Fjavascript%2Freference%2Fglobal_objects%2Fobject%2Fobject%2Findex.md%0A*+Last+commit%3A+https%3A%2F%2Fgithub.com%2Fmdn%2Fcontent%2Fcommit%2F688f606b78fb7e375e5680cc1ae49c5b9d0bc0ea%0A*+Document+last+modified%3A+2023-09-08T00%3A04%3A14.000Z%0A%0A%3C%2Fdetails%3E
"This will take you to GitHub to file a new issue.")

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parent, the  [ Mozilla Foundation ](https://foundation.mozilla.org/) .  
Portions of this content are Â©1998â  2024  by individual mozilla.org
contributors. Content available under  [ a Creative Commons license ](/en-
US/docs/MDN/Writing_guidelines/Attrib_copyright_license) .

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                 Deprecated
                
               ]: Deprecated. Not for use in new websites.
um ](https://discourse.mozilla.org/c/mdn/236)
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##  Developers

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US/docs/MDN/Writing_guidelines/Attrib_copyright_license) .

  *[
                
                 Deprecated
                
               ]: Deprecated. Not for use in new websites.
s%2Fweb%2Fjavascript%2Freference%2Fglobal_objects%2Fobject%2Fhasownproperty%2Findex.md%0A*+Last+commit%3A+https%3A%2F%2Fgithub.com%2Fmdn%2Fcontent%2Fcommit%2F619eb04efb7c6171fd4385fd4ba926805ee08a35%0A*+Document+last+modified%3A+2024-01-15T21%3A56%3A52.000Z%0A%0A%3C%2Fdetails%3E
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##  MDN

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parent, the  [ Mozilla Foundation ](https://foundation.mozilla.org/) .  
Portions of this content are Â©1998â  2024  by individual mozilla.org
contributors. Content available under  [ a Creative Commons license ](/en-
US/docs/MDN/Writing_guidelines/Attrib_copyright_license) .

  *[
                
                 Deprecated
                
               ]: Deprecated. Not for use in new websites.
ummary%3E%0A%0A*+Folder%3A+%60en-
us%2Fweb%2Fjavascript%2Freference%2Fglobal_objects%2Fobject%2Fissealed%60%0A*+MDN+URL%3A+https%3A%2F%2Fdeveloper.mozilla.org%2Fen-
US%2Fdocs%2FWeb%2FJavaScript%2FReference%2FGlobal_Objects%2FObject%2FisSealed%0A*+GitHub+URL%3A+https%3A%2F%2Fgithub.com%2Fmdn%2Fcontent%2Fblob%2Fmain%2Ffiles%2Fen-
us%2Fweb%2Fjavascript%2Freference%2Fglobal_objects%2Fobject%2Fissealed%2Findex.md%0A*+Last+commit%3A+https%3A%2F%2Fgithub.com%2Fmdn%2Fcontent%2Fcommit%2F2ae5490e54b413897242860dfe2328e825773bda%0A*+Document+last+modified%3A+2024-03-22T13%3A49%3A01.000Z%0A%0A%3C%2Fdetails%3E
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##  MDN

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Portions of this content are Â©1998â  2024  by individual mozilla.org
contributors. Content available under  [ a Creative Commons license ](/en-
US/docs/MDN/Writing_guidelines/Attrib_copyright_license) .

  *[
                
                 Deprecated
                
               ]: Deprecated. Not for use in new websites.
<!-- With style containment -->
    <span class="open-quote">
      outer
      <span style="contain: style;">
        <span class="open-quote"> inner </span>
      </span>
    </span>
    <span class="close-quote"> close </span>
    <br />
    <!-- Without containment -->
    <span class="open-quote">
      outer
      <span>
        <span class="open-quote"> inner </span>
      </span>
    </span>
    <span class="close-quote"> close </span>
    

css
c2445ce1dc3a0170e2fbfdbee10e18a7455c2282%0A*+Document+last+modified%3A+2023-09-12T02%3A17%3A31.000Z%0A%0A%3C%2Fdetails%3E
"This will take you to GitHub to file a new issue.")

[ MDN logo  ](/)

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  * [ MDN on GitHub  ](https://github.com/mdn/)
  * [ MDN Blog RSS Feed  ](/en-US/blog/rss.xml)

##  MDN

  * [ About ](/en-US/about)
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  * [ MDN Community ](/en-US/community)
  * [ MDN Forum ](https://discourse.mozilla.org/c/mdn/236)
  * [ MDN Chat ](/discord)

##  Developers

  * [ Web Technologies ](/en-US/docs/Web)
  * [ Learn Web Development ](/en-US/docs/Learn)
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  *[
                
                 Deprecated
                
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0A%3Cdetails%3E%0A%3Csummary%3EPage+report+details%3C%2Fsummary%3E%0A%0A*+Folder%3A+%60en-
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