When you need to restrict user to enter negative numbers in input text field,
You can achieve using plain JavaScript & jQuery as explained in below video.
It will also not allow user to enter alphabet letters like A to Z.
Please leave your suggestions & comments if you found above code useful, so when other person read this blog, he/she can use above code with confidence.
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Full Stack Web Developer 
Saved as a favorite, I really like your website!
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What’s up, just wanted to mention, I enjoyed this blog post.
It was helpful. Keep on posting!
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Using ‘OR’ is correct ,otherwise it shows alert only for negative strings.
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Thats true..!!!
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Its not working for negative numbers.
For that we have to put ‘OR’ condition instead of ‘AND’ condition as follows :
value = document.getElementById(‘ID’).value;
if (parseInt(value) < 0 && isNaN(value))
{
alert("please enter valid values");
document.getElementById('iD').value = ' ';
document.getElementById('iD').focus();
}
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Hello subha,
Thanks for your feedback.
We cant put if (parseInt(value) < 0 && isNaN(value)) because if one of 2 condition will not satisfy , then it will not validate.
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Dear Nilesh,
Thanks For your Feedback..
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its relay work
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