SP.FieldText.maxLength property (sp.js)
Gets or sets a value that specifies the maximum number of characters allowed in the value of the field.
Applies to: apps for SharePoint | SharePoint Foundation 2013 | SharePoint Server 2013
var value = SP.FieldText.get_maxLength ()
var value = SP.FieldText.set_maxLength ()
Return value
Type: Number
Remarks
Its value must be equal to or greater than 1. Its value must be equal to or less than 255.