You can hold down the right Alt key to be able to select text within a link with the mouse.

tried both alt keys still not able to highlight it

Provide steps to replicate your issue. What site is that?

https://www.partzilla.com/catalog/honda/atv/1986/trx250-a-fourtrax-250/handle-lever here is another page, left click and hold, dragging across the part number text to highlight it

https://www.partzilla.com/catalog/honda/atv/1986/trx250-a-fourtrax-250/handle-lever left house click and hold, dragging across part number text trying to highlight it

https://www.partzilla.com/catalog/honda/atv/1986/trx250-a-fourtrax-250/handle-lever left house click and hold, dragging across part number text trying to highlight it

Thank you for the link. The number is actually on a button styled as a link. Firefox doesn't allow selecting the text of buttons.

There is a way to override that using an add-on. This is basically a global rule to allow selection under most circumstances (it's not perfect, but it does help in this case). Here's how:

(1) Install the Stylus extension: https://addons.mozilla.org/firefox/addon/styl-us/

This add-on lets you apply custom style rule overrides to web pages.

(2) Find the Stylus "S" button on the toolbar or Extensions button drop-down list, click that button, then click Manage to open a new tab with the Stylus dashboard.

(3) Under Actions, click the "Write new style" button. In the first field at the left, enter a name like Can Select and on the right side, paste this code:

/*** Can Select -- override anti-selection CSS ***/

 /* selectors covering most sites */
html, body, body *
{
    -moz-user-select: auto !important;
    -khtml-user-select: auto !important;
    -webkit-user-select: auto !important;
    -ms-user-select: auto !important;
    user-select: auto !important;
}

Then click Save. The next time you try the problem page, you should be able to select and copy.

thanks! just followed your instructions and it works like it did on chrome. have a good new year