Yes, JS can be used to prevent invalid entries. The -9 requirement makes it a bit complicated.

https://community.qualtrics.com/XMcommunity/discussion/comment/50598#Comment_50598Do you know maybe how to do it TomG ? I have some questions with positive integers only and your code (screenshot below) works great. But I'm not sure how to deal with the -9 condition.

https://community.qualtrics.com/XMcommunity/discussion/comment/50644#Comment_50644Yes, in theory. Start with the code above, change the regex to allow digits and minus, and add additional logic.

Hi there, if you still need, I was able to follow TomG's recommendation and adding the below JS to the OnReady of the question is working on my end. All characters that are not digits or hyphens are replaced with nothing and then also any digit 0-8 preceded by a hyphen gets replaced with nothing:
jQuery("#"+this.questionId+" input[type=text]").attr( { 
oninput:"event.target.value = event.target.value.replace(//^0-9-]*/g,'');event.target.value = event.target.value.replace(/--0-8]/g,'')"
} );

https://community.qualtrics.com/XMcommunity/discussion/comment/50929#Comment_50929Unfortunately, that allows invalid values like:
-9123
---987---
-9-9-9
etc.
Also, rather than add an oninput attribute, a cleaner way to do the same thing is:
jQuery("#"+this.questionId+" input[type=text]").on("input", function() { 
this.value = this.value.replace(/(^0-9-]*/g,'').replace(/-/0-8]/g,'');
});

Ah true! And thank you very much for the cleaner code. I tweaked it a bit to address the invalid values and I think this is close:
jQuery("#"+this.questionId+" input[type=text]").on("input", function() { 

this.value = this.value.replace(//^0-9-]*/g,'').replace(/--0-8-]/g,'').replace(//0-9]-/g,'');

var text = this.value;
var lefttext = text.charAt(0);

if(lefttext=='-') {
  jQuery(this).attr('maxlength',2);
}

});
The 3 replacements going on:

• Replace all characters that are not digits or hyphens


• Replace all digits 0-8 if they are preceded by a hyphen (includes double hyphen) ("-8", "--")


• Replace all digits where a hyphen follows 0-9 ("999---")

https://community.qualtrics.com/XMcommunity/discussion/comment/50936#Comment_50936Hy Tom_1842,
it seems that this is working as I planned! Thank you so much. Do you know if maybe the export for this question will look different because of this condition? By that I mean if someone enters for example 65, and then deletes it and enters -9, will the export show only -9?
Thank you once again.

https://community.qualtrics.com/XMcommunity/discussion/comment/51181#Comment_51181It won’t look any different - the export will show -9.

Tom_1842 just a quick update on your code. So there was actually a small problem because when respondents entered -9 they could delete it and enter only 2 numbers. So let's say somebody changed their mind and after -9 and wished to enter 5000. They could enter only 50. After they entered 0, they could delete it and enter only 1 number. I just adapted your code so now it looks like this:
Qualtrics.SurveyEngine.addOnload(function()
{
jQuery("#"+this.questionId+" input[type=text]").on("input", function() { 

this.value = this.value.replace(//^0-9-]*/g,'').replace(/--0-8-]/g,'').replace(//0-9]-/g,'').replace(//^0-]-/g,'');

var text = this.value;
var lefttext = text.charAt(0);

if(lefttext=='-') {
  jQuery(this).attr('maxlength',2);
} else if (lefttext=='')
jQuery(this).attr('maxlength',20);
if(lefttext=='0') {
  jQuery(this).attr('maxlength',1);
} else if (lefttext =='') {
jQuery(this).attr('maxlength',20);
}
});
});

I'm not sure this is the best way to handle it, but it works.

dmus and Tom_1842 ,
This has gone down the wrong track. Here is a much cleaner approach:
Qualtrics.SurveyEngine.addOnReady(function() {
jQuery("#"+this.questionId+" td input[type=text]").on("input",function() {
var val = this.value.replace(/[^\\d-]/g,"");
if(val=="" || val =="-") this.value = val;
else {
val = parseInt(val);
if(val==-9 || val>=0) this.value = val;
else if(val<=-90) this.value = -9;
else this.value = "-";
}
});
});

dmus ah that makes sense, I didn't think about that but I'm glad you were able to adapt the code to address it. TomG's code is indeed much cleaner though, I'd swap that in for your project if you can. Thank you TomG for your expertise!