redirect knockout js observable if containing string
I have a input field in my html which basically sends the amount to an observable and then redirects to different pages depending on the amount, but I want to make sure that even if a person who doesnt write amount and types in "string values" should still be able to get redirected, but I am not sure how to accomplish that.
HTML CODE
<input id="amount" type="text" data-bind="value : amount" />
<button class="btn button2" type="submit" data-bind=" valueUpdate:'afterkeydown' , click: $root.borrow_first_pageview" ></button>
I do not want to write the type= number in the HTML since I want to know how its checked in the JS.
here is the rest code using knockout.js
self.borrow_first_pageview = function () {
if(self.amount()){
window.location.href = BASEURL + "index.php/moneyexchange/borrow_first_page/" + self.amount();
}else if(typeof self.amount() == 'string'){
window.location.href = BASEURL + "index.php/moneyexchange/borrow_first_page/" + 2500;
}else {
window.location.href = BASEURL + "index.php/moneyexchange/borrow_first_page/" + 2500;
}
};
Is there a way to check if self.amount() is a String and then redirect the user. Need help.
So we can reverse the problem and see if the amount is a number or not and then act accordingly:
var value = self.amount();
if((+value == value) && !isNaN(+value)){
//Yey we have a valid number.
}
This is probably one of the few valid uses of a loose equality operator I have found (it guards against null and "" being passed in). It uses the unary plus operator plus a little bit of magic and it's a nice short way of checking if a value is a number or not.
You can put this into a function if you like, 'IsNumber' for example:
function isNumber(value){
//loose equality operator used to guard against nulls, undefined and empty string
return ((+value == value) && !isNaN(+value));
}
上一篇: 只允许某些类型的属性