javascript / jQuery：验证来自.val（）的数字

Question

I'm validating my form, just checking if in the fields where a number should be the user has entered an string. But as I'm getting all the field values like this:

var number=  $("#number").val();

All my variables are strings.

alert(typeof number);

shows "string" with all numeric fields values.

Any ideas on how can I validate integers??

Thanks a lot

Answer 1

You can use

jQuery.isNumeric( value ) 

method for this purpose. As a result you don't need any extra parsing effort.

DEMO

Read more about $.isNumeric()

For manual parse(if you don't use above)

var number = parseInt($("#number").val(), 10);

and for check

if(isNaN(number)) {
   // do something
} else {
   // do something else
}

Answer 2

isNaN(parseInt($("#number").val())); should do the trick! If you want to work with the number at all, this might be an easier way:

var value = parseInt($("#number").val());

if (isNaN(value)) {
  console.log("invalid input");
} else {
  console.log("user entered: " + value);
}