Limit writing more chars field address line

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Hello,

Someone can help me please, in my store when customers registrate they have to fill the fields with details.

 

In the fiel address i have a limited size of 50 chars per line, but what I want is when you reach 50 characters, don't let me write any more characters, that is, block it in the 50 characters and have to write the rest on the bottom line

 

Can someone tell what code i have to add and where please ?

 

Thanks alot