Can you set a border opacity in CSS

Question

Is there a straight forward CSS way to make the border of an element semi-transparent with something like this   border-opacity  0 7    If not  does anyone have an idea how I could do so without using images

User · Answer

As an alternate solution that may work in some cases  change the border-style to dotted   Having alternating groups of pixels between the foreground color and the background color isn t the same as a continuous line of partially transparent pixels  On the other hand  this requires significantly less CSS and it is much more compatible across every browser without any browser-specific directives

User · Answer

Other answers deal with the technical aspect of the border-opacity issue  while I d like to present a hack pure CSS and HTML only   Basically create a container div  having a border div and then the content div    lt div class  container  gt     lt div class  border-box  gt  lt  div gt     lt div class  content-box  gt  lt  div gt   lt  div gt    And then the CSS  set content border to none  take care of positioning such that border thickness is accounted for    container     width  20vw    height  20vw    position  relative     border-box     width  100     height  100     border  5px solid black    position  absolute    opacity  0 5     content-box     width  100     height  100     border  none    background  green    top  5px    left  5px    position  absolute

User · Answer

It s easy  use a solid shadow with 0 offset    foo     border-radius  1px    box-shadow  0px 0px 0px 8px rgba 0 0 0 0 3              Also  if you set a border-radius to the element  it gives you pretty rounded borders  jsFiddle Demo

User · Answer

Not as far as i know there isn t what i do normally in this kind of circumstances is create a block beneath with a bigger size  bordersize 2  originalsize  and make it transparent using  filter alpha opacity 50   -moz-opacity 0 5  -khtml-opacity  0 5  opacity  0 5    here is an example   main      width 400px      overflow hidden      position relative     border      width 100       position absolute      height 100       background-color  F00      filter alpha opacity 50       -moz-opacity 0 5      -khtml-opacity  0 5      opacity  0 5     content      margin 15px   size of border       background-color black     lt div id  main  gt       lt div class  border  gt       lt  div gt       lt div class  content  gt          testing      lt  div gt   lt  div gt    Update   This answer is outdated  since after all this question is more than 8 years old  Today all up to date browsers support rgba  box shadows and so on  But this is a decent example how it was 8  years ago

User · Answer

try this    lt h2 gt Snippet for making borders transparent lt  h2 gt   lt div gt     lt p gt Lorem ipsum dolor sit amet  consectetur adipiscing elit  Integer nec odio  Praesent libero  Sed cursus ante dapibus diam  Sed nisi  Nulla quis sem at nibh elementum imperdiet  Duis sagittis ipsum  Praesent mauris  Fusce nec tellus sed augue semper porta      Mauris massa  Vestibulum lacinia arcu eget nulla   lt b gt Lorem ipsum dolor sit amet  consectetur adipiscing elit lt  b gt   Class aptent taciti sociosqu ad litora torquent per conubia nostra  per inceptos himenaeos  Curabitur sodales ligula in libero  Sed dignissim     lacinia nunc   lt i gt Lorem ipsum dolor sit amet  consectetur adipiscing elit lt  i gt   Curabitur tortor  Pellentesque nibh  Aenean quam  In scelerisque sem at dolor  Maecenas mattis  Sed convallis tristique sem  Proin ut ligula vel nunc egestas porttitor       lt i gt Lorem ipsum dolor sit amet  consectetur adipiscing elit lt  i gt   Morbi lectus risus  iaculis vel  suscipit quis  luctus non  massa  Fusce ac turpis quis ligula lacinia aliquet  Mauris ipsum  Nulla metus metus  ullamcorper vel  tincidunt sed  euismod     in  nibh  Quisque volutpat condimentum velit  Class aptent taciti sociosqu ad litora torquent per conubia nostra  per inceptos himenaeos  Nam nec ante  Sed lacinia  urna non tincidunt mattis  tortor neque adipiscing diam  a cursus ipsum ante quis     turpis  Nulla facilisi  Ut fringilla  Suspendisse potenti  Nunc feugiat mi a tellus consequat imperdiet  Vestibulum sapien  Proin quam  Etiam ultrices   lt b gt Nam nec ante lt  b gt   Suspendisse in justo eu magna luctus suscipit  Sed lectus   lt i gt Sed convallis tristique sem lt  i gt       Integer euismod lacus luctus magna   lt b gt Class aptent taciti sociosqu ad litora torquent per conubia nostra  per inceptos himenaeos lt  b gt   Quisque cursus  metus vitae pharetra auctor  sem massa mattis sem  at interdum magna augue eget diam  Vestibulum     ante ipsum primis in faucibus orci luctus et ultrices posuere cubilia Curae  Morbi lacinia molestie dui  Praesent blandit dolor  Sed non quam  In vel mi sit amet augue congue elementum  Morbi in ipsum sit amet pede facilisis laoreet  Donec lacus nunc      viverra nec  blandit vel  egestas et  augue  Vestibulum tincidunt malesuada tellus  Ut ultrices ultrices enim   lt b gt Suspendisse in justo eu magna luctus suscipit lt  b gt   Curabitur sit amet mauris  Morbi in dui quis est pulvinar ullamcorper   lt  p gt   lt  div gt   lt div id  transparentBorder  gt    This  amp lt div amp gt  has transparent borders   lt  div gt    And here comes our magical CSS          padding  10pt    font  13px 1 5 Helvetica Neue  Arial  Helvetica   Liberation Sans   FreeSans  sans-serif     b     font-weight  bold     i     font-style  oblique     H2     font-size  2em     div id  transparentBorder       height  100px    width  200px    padding  10px    position  absolute    top  40     left  30     text-align  center    background  Black    border-radius  4px    border  10pt solid rgba 0  0  0  0 5     -moz-background-clip  border       Firefox 3 6      -webkit-background-clip  border       Safari 4  Chrome 6       background-clip  border-box       Firefox 4  Safari 5  Opera 10  IE 9      -moz-background-clip  padding       Firefox 3 6      -webkit-background-clip  padding       Safari 4  Chrome 6       background-clip  padding-box       Firefox 4  Safari 5  Opera 10  IE 9      text-align  center    margin  0    color   fff    cursor  pointer      Check out the Demo here

User · Answer

If you check your CSS coding with W3C validator  you will see if your CSS code is acceptable  even if it worked in the major browsers   Creating a transparent border via CSS  as written above    border  1px solid rgba 255  0  0   5     is not accepted by W3C standards  not even for CSS3  I used the direct input validator with the following CSS code     test   border  1px solid rgba 255  0  0   5       The results were       Value Error   border Too many values or values are not recognized     1px solid rgba 255 0 0 0 5     Unfortunate that the alpha value  the letter  a  at the end of  rgb   is not accepted by W3C as part of the border color values as yet  I do wonder why it is not standardized  since it works in all browsers  The only hitch is whether you want to stick to W3C standards or step aside from it to create something in CSS   To use W3C online CSS validator   Direct Input   Always a good idea to use a validator to check your work  it really helps finding small or even large errors in coding when your going cross-eyed after hours of coding work

User · Answer

Unfortunately the opacity element makes the whole element  including any text  semi-transparent  The best way to make the border semi-transparent is with the rgba color format  For example  this would give a red border with 50  opacity   div       border  1px solid rgba 255  0  0   5       -webkit-background-clip  padding-box     for Safari        background-clip  padding-box     for IE9   Firefox 4   Opera  Chrome        The problem with this approach is that some browsers do not understand the rgba format and will not display any border at all if this is the entire declaration  The solution is to provide two border declarations  The first with a fake opacity  and the second with the actual  If a browser is capable  it will use the second  if not  it will use the first   div       border  1px solid rgb 127  0  0       border  1px solid rgba 255  0  0   5       -webkit-background-clip  padding-box     for Safari        background-clip  padding-box     for IE9   Firefox 4   Opera  Chrome        The first border declaration will be the equivalent color to a 50  opaque red border over a white background  although any graphics under the border will not bleed through    UPDATE  I ve added  background-clip  padding-box   to this answer  per  SooDesuNe s suggestion in the comments  to ensure the border remains transparent even if a solid background color is applied

User · Answer

No  there is no way to only set the opacity of a border with css    For example  if you did not know the color  there is no way to only change the opacity of the border by simply using rgba

User · Answer

As others have mentioned  CSS-3 says that you can use the rgba      syntax to specify a border color with an opacity  alpha  value     here s a quick example if you d like to check it      It works in Safari and Chrome  probably works in all webkit browsers     It works in Firefox I doubt that it works at all in IE  but I suspect that there is some filter or behavior that will make it work    There s also this stackoverflow post  which suggests some other issues--namely  that the border renders on-top-of any background color  or background image  that you ve specified  thus limiting the usefulness of border alpha in many cases

[css] Can you set a border opacity in CSS?

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