Code Keeps Getting Deleted

This is part of the code I’m using for my MailChimp signup form:

< input id="mce-FNAME" class="" name="FNAME" size="30" type="text" value="Enter your name" placeholder="Enter your name" onfocus="if(this.value==this.defaultValue)this.value='';"
onblur="if(this.value=='')this.value=this.defaultValue;" />

and it works fine until I decide to go back and edit something. The

onfocus="if(this.value==this.defaultValue)this.value='';"
onblur="if(this.value=='')this.value=this.defaultValue;"

part of the code gets deleted.

Website: https://7sigmaphysiques.com/

Thanks in advance!

Hello,

Where exactly you add that code?

Kind Regards, Roman.