How to append javascript varible without using jQuery?

Question

I've simple javascript function mentioned below:

<script>
    function getValue(val)
    {
      document.getElementById('answer').value = val;
    }
</script>

This function get's called on click of span and returned value gets displayed in input text. I've three questions:

1] On click of span, if I want to append current value of varible 'val' with previous value; and return appended value to calling function. can you please suggest, how to achieve same without using jQuery?

2] There is one span which is suppose to work like Backspace. So click of span, i want to remove last character from document.getElementById('answer').value [This also without using jQuery]

3] There is one span which is suppose to work like Navigation keys [Right & Left]. So click of span [Let's say right], i want to move cursor position of the input text one character right and similarly for Left [This also without using jQuery]

Can you please suggest some pointers to achieve this?

@HithamS.AlQadheeb Please help me in figuring out the connection between these two topics... — , Jan 01 '14 at 08:26

score 1 · Accepted Answer · edited May 23 '17 at 10:25

For your question 1 I think you can do below. Code not tested

function getValue(val)
{
var currentVal = document.getElementById('answer').value
if(currentVal.length > 0 )
  currentVal = parseInt(currentVal);
      document.getElementById('answer').value = currentVal + val;
}

For question 2 :

Get the value and then do string operation to remove the last char. Its easy little google search for the string operations

For question 3 :

you can use event oncontextmenu for right click. Example below.

How can I capture the right-click event in JavaScript?

For moving cursor check below

Set keyboard caret position in html textbox

Thanks for providing pointers for all three questions. – Pawan Mude Jan 01 '14 at 08:51 — Pawan Mude, Jan 01 '14 at 08:51

Zaheer Ahmed · Answer 2 · 2014-01-01T08:30:39.413

1

+= oprator appends string to existing string(not applicable in this case).
use return keyword to return updated value.
for removing last character use substring.

so try:

function getValue(val)
{
  var currentText = document.getElementById('answer').value;
  var updatedText = currentText.substring(0,currentText.length-2) +  val;
  document.getElementById('answer').value = updatedText;
  return updatedText;
}

edited Jan 01 '14 at 08:30

answered Jan 01 '14 at 08:24

Zaheer Ahmed

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Thanks Zaheer ; this is very much useful. – Pawan Mude Jan 01 '14 at 08:49

How to append javascript varible without using jQuery?

2 Answers2