problem in Spry validation

hello,

i am using spry framework in Adobe Dreamweaver CS3 and i am working on its validations, its works fine, but on one textfield, i want to apply validation so that it cannot accept numeric characters, means the input field just accept characters.
please tell me that how can i write its validation. i tried this , but it is for just integer values.

//var sprytextfield2 = new Spry.Widget.ValidationTextField("sprytextfield2", "integer", {validateOn:["blur"]});

thanks