Only one comma at a time

[haolan]

Hey

 

I am about to make a wannabe calculator, and i wanna make sure that my users can only write one comma in the display.

My buttons are "on screen" so when i click the comma button i need to whether there already is a comma in the display (which is a textbox). If so, it may just ignore the press on the button.

 

How do I make that check?

[Karl33to]

if (document.formName.fieldName.value.indexOf(',') !=-1){
// a comma exists, so do something here
}

 

also, call me picky, but calculators don't have a comma button on them! 

 

[haolan]

hehe i know.. but i am from Denmark.. And in Denmark we use comma instead of period

[haolan]

hmm but your code does not work..

 

<script type="text/javascript">

function tjekComma() {

if (document.profit_form.profit_display.value.indexOf(',') !=-1) {

// DO NOTHING!

} else {

document.profit_form.profit_display.value = document.profit_form.profit_display.value += ',';

}

</script>

 

i can still add a lot of commas... I have tried to put the document.profit..blablabla.. in the if instead of else.. But it wont work anyway..

 

 

[gurroa]

See php.gurroa.cz/test/simplecalc.html.

You still have to use period in math operations.

And also try to test result if somethings doesn't work,

like what result are you getting from this function

document.profit_form.profit_display.value.indexOf(',')