You can use the Exit event of the TextField to test..
Only if the user uses enter key then a new line character is added to the field.
If the user enters the text without using enter key to goto next line, then the field will wrap the text and without a new line character. In that case, it will be treated as a single line.
var xx = TextField1.rawValue.split(/\r\n|\r|\n/);
for(i=0;i<xx.length;i++){
xfa.host.messageBox("" + xx[i]);
}
Thanks
Srini