html contentEditable document.execCommand change selected opacity

问题

any one worked with changing opacity on contentEditable selected.

I tried with following:

document.execCommand('foreColor', false, 'rgba(0,0,0,0.5)'); // with rgba
document.execCommand('foreColor', false, '80000000'); // with alpha hex

none worked. but i can easily change colour with:

document.execCommand('foreColor', false, '000000');

Can anyone help me on change opacity with document.execCommand ?

Update

On further searching found out:

document.execCommand 'foreColor' add font tag to selected with given colour. But sadly the color attribute of is not supported in HTML5.

is thats the problem ? what is its alternative ?

回答1:

You will have to use the styleWithCSS command, which specifies whether CSS or HTML formatting should be generated by the execCommand method into the document.

Refer the specs here: https://dvcs.w3.org/hg/editing/raw-file/tip/editing.html#the-stylewithcss-command .

So, in this case pass true to use the CSS styling instead of generating the font tag.

Snippet:

function setColor() {
    document.execCommand('styleWithCSS', false, true);
    document.execCommand('foreColor', false, "rgba(0,0,0,0.5)");
}

<p contentEditable="true" onmouseup="setColor();">this is some text</p>

This will generate HTML with CSS applied, like this:

<p contenteditable="true" onmouseup="setColor();">
    this is <span style="color: rgba(0, 0, 0, 0.498039);">some</span> text
</p>

Hope that helps.

.

来源：https://stackoverflow.com/questions/27441062/html-contenteditable-document-execcommand-change-selected-opacity