在提交按钮之前如何验证数据？

Question

I have this code jsFiddle . What I'm trying to accomplish is the following. As the user clicks the 'Ok' button inside the dialog, I want the code to compute whether the date at 'field1' is after 'field2', meaning, the current period is after the previous (as it should). If this is so, I want the action to continue, populate the textboxes and close the dialog. Whenever that is not true, I want to alert the user that the selections made, were invalid (Previous cannot come after Current). I do not have a problem with the date math (the plugin date.js makes it easy enough), I am having problems when it comes to trying to figure out where to include this condition. Any help will be appreciated, feel free to change the code and post your results here. Thanks.

I have a feeling the code should go just before closing the dialog, but I cannot get the right conditions to make it so, eg:

//code up to here handles 'if's and 'else's
var currentPeriod = $("input#field1").val()
var previousPeriod = $("input#field2").val()

 d1 = Date.parse(currentPeriod);
 d2 = Date.parse(previousPeriod); 

if((Date.compare(d1,d2))=='1')
{
  $(this).dialog("close");
 }
else
  {
   alert("Invalid date range");
 }

Answer 1

What you wrote above, using Date.compare() is mostly correct. Documentation on the compare is here .

There are two points on it though:

• That code isn't anywhere in the fiddle you put together.
• In your fiddle $("input#field1") and #("input#field2") would refer to the input boxes, not the dialog select boxes. You want to do the validation before you assign the values to the input boxes, otherwise you close the dialog and it doesn't matter as the values are already assigned.

Where it should go (based on the fiddle) is at the beginning of the function that gets called when the the OK button is clicked. Right now it looks like you're doing handling the current date and putting the value in the input boxes, then handling the previous date and assigning the values. You would need to check if the values are before one another before any of this happened.