16. A method comprising: displaying with a computing device an electronic form with first and second data-entry fields associated with first and second nodes in a hierarchical data file written in XML; enabling a user to input data into the first data-entry field through the computing device, the data being storable in the first node; receiving data input into the first data-entry field; validating the data, locally on the computing device, with a validation rule, in real time, and prior to enabling the user to input second data into the second data-entry field, to determine if the data is valid or invalid, wherein the validation rule is based on a part of a schema containing logic that governs the hierarchical data file, wherein the logic sets forth bounds of what data nodes the file can contain or the structure the nodes should have, and wherein the validation rule governs a node group of the hierarchical data file which includes the first node, and wherein validating is based on third data stored in a third node belonging to the node group, the third data having been entered into a third data-entry field mapped to the third node; and enabling the user to input the second data into the second data-entry field if the data input into the first data-entry field is valid, the second data being storable in the second node, or alerting the user if the data input into the first data-entry field is invalid.
16. A method comprising: displaying with a computing device an electronic form with first and second data-entry fields associated with first and second nodes in a hierarchical data file written in XML; enabling a user to input data into the first data-entry field through the computing device, the data being storable in the first node; receiving data input into the first data-entry field; validating the data, locally on the computing device, with a validation rule, in real time, and prior to enabling the user to input second data into the second data-entry field, to determine if the data is valid or invalid, wherein the validation rule is based on a part of a schema containing logic that governs the hierarchical data file, wherein the logic sets forth bounds of what data nodes the file can contain or the structure the nodes should have, and wherein the validation rule governs a node group of the hierarchical data file which includes the first node, and wherein validating is based on third data stored in a third node belonging to the node group, the third data having been entered into a third data-entry field mapped to the third node; and enabling the user to input the second data into the second data-entry field if the data input into the first data-entry field is valid, the second data being storable in the second node, or alerting the user if the data input into the first data-entry field is invalid. 18. A method of claim 16 , wherein alerting the user includes marking the first data-entry field.