i need dynamically updating value of form submit user types input field.
<form> <input type="text" name="number" id="number" value = 0 /> <input type="submit" id="submit"> </form> <script> var amount = 100; var number = document.getelementbyid('number').value; var total = amount + number; var = document.getelementbyid("submit"); a.value = "pay $" + total; </script> right now, value of submit "pay 100". when user enters 4 in number field, want "pay 104" types 4. want user delete , enter different number , value changes accordingly. how achieve this? in advance.
try this..
document.getelementbyid('number').addeventlistener("input", function(){ if(this.value.length && !isnan(parseint(this.value))){ var total = amount + parseint(this.value); submit.value = "pay $"+ total; } }, false); var amount = 100; var submit = document.getelementbyid("submit"); document.getelementbyid('number').addeventlistener("input", function(){ if(this.value.length && !isnan(parseint(this.value))){ var total = amount + parseint(this.value); submit.value = "pay $"+ total; } }, false);<form> <input type="text" name="number" id="number" value = 0 /> <input type="submit" id="submit"> </form>