Question

I have already got this working, but I know there must be a more succinct way of doing it.

Using onBlur on a text field in the html page, it calls a method which replaces the value of the string if the value is empty or NaN.

JS:

function checkStr(str) {
        return str.value = "0";
}

HTML:

onblur="if(this.value=='' || isNaN(this.value)){this.value=checkStr(this.value)};"

So this does work, but seems exhaustive. Using:

function checkStr(str) {
    if (str.value == "" || isNaN(str.value)) {
        return str.value = "0";
    }
}

In the JS file, and:

onblur="checkStr(this.value);" 

In the HTML doesn’t work.

Any ideas?

Answer 1

Your second method isn’t assigning anything to textbox value, so you really need the following , i.e. passing in the textbox into the function

onblur="checkStr(this);"

and then for the function to check and assign the textbox

function checkStr(textbox) {
    if (textbox.value == "" || isNaN(textbox.value)) {
        textbox.value = "0";
    }
}