knockout.js - knockout get old value of the text box -

i'm using mapping plugin. have on 'blur' event whenever takes away focus text box. know if old value different new value. works correct "enter" key. reason whenever change value , press enter console output first time; 'oldvalue | newvalue'. not case when 'blur' fires. 'newvalue | newvalue'

how come?. how can new , old values on blur?

html:

<input class="percent-text" data-bind="text: percent, value: percent, event: { keypress: $root.percentupdate, blur: $root.percentupdate }" type="number" min="1" max="100" oninput="maxlength(this)" maxlength="3" /> 

knockout:

    self.percentupdate = function (data, event) {         if (event.keycode === 13 || event.type == 'blur') {             var $target = $(event.currenttarget);             console.log(data.percent() + " | " + event.target.value);          }         return true;     }; 

knockout updates value on blur , value getting updated before blur event. don't know you're trying do, using .subscribe , .subscribe beforechange.

http://knockoutjs.com/documentation/observables.html

for example

data.percent.subscribe(function(newvalue) {     alert(newvalue) }); 

and

data.percent.subscribe(function(oldvalue) {         alert(oldvalue)     }, null, "beforechange");