Drop down selection triggers predefined text in text box

Thank you Again @Nesa Nurani for your help . Im trying to apply principle this to a different form with formatting I have placed the scipt in the custom validation . Once the onformation is entered and the dropdown selected nothing populates in the "Calc_Text" Field. Would you mind looking it over for me ? 

event.target.richText=true;

var w1 = this.getField("DD_Writer").valueAsString;
var w2 = this.getField("Calc_WriterPosition").valueAsString;
var w3 = this.getField("Calc_WriterPhoneNumber").valueAsString;
var w4 = this.getField("Calc_WriterEmail").valueAsString;
var m1 = this.getField("Date_LetterDate").valueAsString;
var m2 = this.getField("ResidentName").valueAsString;
var m3 = this.getField("DD_Property").valueAsString;
var m4 = this.getField("Date_AptDate").valueAsString;
var m5 = this.getField("DD_Time").valueAsString;
var m6 = this.getField("Date_IncreaseDate").valueAsString;
var r = this.getField("Calc_Text");

if(event.value == "VCL Attempt #1"){
r.value =

spans = new Array();
spans[0] = new Object();
spans[0].text = m1 + "\n\n\n\nDear, " + m2 +
"\n\nThank you for being a valued resident at " + m3 + "." +
"\n\nIt is time for your annual review. As you may remember when wntering the " + m3 + " Program, you were advised that every year we would review your income and adjust your rent as needed. This is required for every resident in the program. Although, rent adjustments may have reciently orrurred, it is required by our contract to review everyone's income at their annual annaversary.";

spans[1] = new Object();
spans[1].text ="\n\nI have schedueled a time for youto come to the office and complete this process on ";
spans[1].fontWeight=900;

spans[2] = new Object();
spans[2].text = m4 + " At " + m5 + ".";
spans[2].fontWeight = 900;
spans[2].underline = true;

spans[3] = new Object();
spans[3].text ="\n\nIf you fail to complete your recertification and provide the requested documentation by that date, your rent will revert to market rate of $650.00 effective ";
spans[3].fontWeight=900;

spans[4] = new Object();
spans[4].text = m6 + ".";
spans[4].fontWeight = 900;
spans[4].underline = true;

spans[5] = new Object();
spans[5].text ="\n\nIf at any time your income frcreases and it is expected to stay that way for at least one month, we will adjust your income immediately. Should your income increase at any time , please notify us immediately. Failue to notify us of income changes may resulyt in back rent owed and late fees." +
"\n\nIf you have any questions on this regarding the income review or any other program policies, please contact your case manager." +
"\n\n\n\n\n\n" + w1 +
"\n" + w2 +
"\nValley Cities Behavioral Health Care" +
"\nCell: " + w3;

event.richValue=spans;
}
else if(event.value == "Others Attempt #1")
r.value = "this part works so far";

else r.value = "hello this is blank ";

Am i correct in thinking that this needs to be a validation script in the DD box or do i need to put my formula in the the text box ?