Yes, this is possible!
Navigate to the folder that contains WebLink Web Files, which should be in Program Files\Laserfiche\WebLink\Web Files. Find CustomSearch.aspx (and make sure that it's .aspx). Right click and open with a text processing application like Notepad.
Find the line that starts with <body (around line 14) and add the following code in the same line right after <body:
onload="javascript:SearchLoad()"
Now add the following code in the <body> section before </body>, preferably near the bottom (I put it after the last </div> before </form>):
<script type="text/javascript">
(function SearchLoad() {
var submitButton = $('input[value=Submit]');
if (submitButton && submitButton.length) {
submitButton[0].onclick = function () {
// hide 'no results yet'
var noSearchRunDiv = document.getElementById('NoSearchRunDiv');
if (noSearchRunDiv) {
noSearchRunDiv.innerHTML = "";
}
// display 'Searching...' box
var LoadingBox = document.createElement("div");
LoadingBox.className = "SearchLoadingBox";
var distFromRight = (document.body.clientWidth / 2 - 80); /* center on whole page */
LoadingBox.style.right = distFromRight + 'px';
var SpinnerIcon = document.createElement("div");
SpinnerIcon.className = "SpinnerIconSmall Spin";
SpinnerIcon.style.marginRight = "5px";
LoadingBox.appendChild(SpinnerIcon);
var MessageDiv = document.createElement("div");
MessageDiv.style.display = "inline-block";
MessageDiv.appendChild(document.createTextNode("<%=m_strings.GetString("STR_RETRIEVING_SEARCH_RESULTS")%>"));
LoadingBox.appendChild(MessageDiv);
document.body.appendChild(LoadingBox);
}
}
})();
</script>
And that's it!