In this post we will discuss how we can limit characters on multiline textboxes in InfoPath 2013 or 2010 in SharePoint 2013 or 2010. Also check oout:
If you are using single line of textboxes in your InfoPath form and you want to restrict users to enter specific number of characters then you can do this by right click on the control and go to properties and you can set the character limits.
But if you make the textbox as multiline then the option to limit number of characters will not come. But still you can do this by using rule in infopath forms.
Open your InfoPath form and then add a new rule (validation rule) (Select the textbox and then from the ribbon click on Home and then Manage Rules). Then set the condition as: The expression and then write string-length(.)>500.
Now publish the form and if you will enter more than 50 characters then it will show message like below: