JS: automatic calculate without click any button

JavaScript
1

halo…i got some javascript problem…i need some help.
i have a hidden form value which contain of the TOTAL., let say the total is rm100.
then i have anohter two radio button and two text box, one radio button for one text box.
for the first radio button & textbox set, the user should insert the percentage; for the second radio button and terxt box set, the user should insert the ringgit malaysia.
then how can i get the value form the hidden and the text box and radio button, it will automatically calcualte the discount rate witout submit any button.
let say i have the hidden total is rm100, then i choose ringgit radio button and insert rm50 into the text box, then below there will display rm50(rm100-rm50)?..plz help…plz guide me some coding…thanx.

2

Dont think I totally understand what you need purple83 but the following script does I think what you need.


<script type="text/javascript">

	function calculateTotal() {
		
		var totalAmt = document.addem.total.value;
		totalR = eval(totalAmt - document.addem.tb1.value);
		
		document.getElementById('update').innerHTML = totalR;
	}

</script>

<form name="addem" action="" id="addem" >	
	<span id="update">100</span>
	<p><input type="text" name="tb1" onkeyup="calculateTotal()"/>first textbox</p>
	
	<input type="hidden" name="total" value="100" />
</form>

See if thats what you need :slight_smile:

3

hi spikeZ,…yaya…thanx alot…almost same as wat i wan…thank you very much…
but if i wan to click the radio button first and then calcualte how? how if i got two kind of text box,? one is ringigt discount, one is percentage discount? thanx

4

Extend the function to see which radio button is selected and use that value as required.


<script type="text/javascript">

	function calculateTotal() {
		
		var totalAmt = document.addem.total.value;

		var val = 0;
		
		for( i = 0; i < document.addem.discount_type.length; i++ ) {
		if( document.addem.discount_type[i].checked == true )
		val = document.addem.discount_type[i].value;
		}
		
		if(val == 'ring') {
			dType = document.addem.tb1.value;
		} else {
			dType = document.addem.tb2.value;
		}
		
		totalR = eval(totalAmt - dType);
		
		document.getElementById('update').innerHTML = totalR;
	}

</script>

<form name="addem" action="" id="addem" >	
	<span id="update">100</span>
	<p><input type="radio" name="discount_type" value="ring" checked > Ring: <input type="text" name="tb1" onkeyup="calculateTotal()"/>first textbox</p>
	<p><input type="radio" name="discount_type" value="percentage" > Percentage: <input type="text" name="tb2"  onkeyup="calculateTotal()"/>Second textbox</p>
	
	<input type="hidden" name="total" value="100" />
</form>