var dl=document.getElementById("suggestions"); dl.parentNode.removeChild(dl);

I don't think there is a universal solution for this. Each site names its form elements and runs its autocomplete/autosuggest scripts differently. For example, Wikipedia sets up a datalist element and then attaches a script to the input box that updates the list every time you type a character. You can rip out the list and then the script will quietly fail and nothing gets displayed. You can try that by pressing Ctrl+Shift+k to open the web console, paste the following (long) line of script next to the caret (>), press Enter, then close the web console again.* var dl=document.getElementById("suggestions"); dl.parentNode.removeChild(dl); But it can't easily be generalized to other sites that use different approaches... ''* If you leave the console open, you can see Wikipedia sending your input to the server for suggestions as you type, and the error when the script tries to update the missing datalist.''