How do I format this code so the date only updates once (when the file name is "Template") and doesn't update once the file name has changed?

[#1]

I'm trying to piece together two bits of Javascript code that I found on these forums, but I'm not experienced in this at all so I keep getting an error message. This is what I have so far:

this.addScript("init", "var f = this.getField(\"Today\") + if (this.documentFileName=="Estimate Template.pdf")) f.value = new Date();");

What argument am I missing in this line of code?

Thanks in advance!

[#2]

I'm trying to piece together two bits of Javascript code that I found on these forums, but I'm not experienced in this at all so I keep getting an error message. This is what I have so far:

this.addScript("init", "var f = this.getField(\"Today\") + if (this.documentFileName=="Estimate Template.pdf")) f.value = new Date();");

What argument am I missing in this line of code?

Thanks in advance!

[#3 · Accepted solution]

Just put this code into a document script:

if (this.documentFileName=="Estimate Template.pdf")
     this.getField("Today").value = new Date();

[#4]

Many, many thanks.