Compare Two Text Fields

Here is my code:

if(document.myForm.minbid.value > parseInt(document.myForm.bid.value)) {
alert('Your bid amount MUST be higher than the starting bid price');
myForm.bid.focus()
return false;}

This is the section I am working with. Now this checks a form field called minbid against a form field called bid. These are both text fields. This works great using this example:

minbid = 20.00
bid = 1.54

In that case the alert will popup because bid is less than minbid, however in this case:

minbid = 20.00
bid = .54

It does NOT show the alert and allows the form to submit. Any ideas here?