This codes behavior is unexpected when you use only the buttons to place chars from the carrot location. It always places the char at the end of the string. If i use the buttons and place the char with the keyboard it does work as expected. Why does this happen and any help with a solution is greatly appreciated.
function getInputSelection(el) {
var start = 0,
end = 0,
normalizedValue, range,
textInputRange, len, endRange;
if (typeof el.selectionStart == "number" && typeof el.selectionEnd == "number") {
start = el.selectionStart;
end = el.selectionEnd;
} else {
range = document.selection.createRange();
if (range && range.parentElement() == el) {
len = el.value.length;
normalizedValue = el.value.replace(/\r\n/g, "\n");
textInputRange = el.createTextRange();
textInputRange.moveToBookmark(range.getBookmark());
endRange = el.createTextRange();
endRange.collapse(false);
if (textInputRange.compareEndPoints("StartToEnd", endRange) > -1) {
start = end = len;
} else {
start = -textInputRange.moveStart("character", -len);
start += normalizedValue.slice(0, start).split("\n").length - 1;
if (textInputRange.compareEndPoints("EndToEnd", endRange) > -1) {
end = len;
} else {
end = -textInputRange.moveEnd("character", -len);
end += normalizedValue.slice(0, end).split("\n").length - 1;
}
}
}
}
return {
start: start,
end: end
};
}
function setBack() {
document.getElementById('user').value =
document.getElementById('user').value.substring(0,
document.getElementById('user').value.length - 1);
}
function moveBack(elId) {
var elem = document.getElementById(elId);
elem.setSelectionRange(elem.value.length,
getInputSelection(elem).start - 1);
elem.focus();
}
function moveForward(elId) {
var elem = document.getElementById(elId);
elem.setSelectionRange(elem.value.length,
getInputSelection(elem).start + 1);
elem.focus();
}
function focusElem(){
var foo =document.getElementById('user');
foo.focus();
}
function setA(){ document.getElementById('user').value += "A"; focusElem();}
function setB(){ document.getElementById('user').value += "B"; focusElem();}
function setC(){ document.getElementById('user').value += "C"; focusElem();}
function setD(){ document.getElementById('user').value += "D"; focusElem();}<input id="user" type="text">
<button type="button" onclick="setBack();">backspace</button>
<button type="button" onclick="moveBack('user')">back</button>
<button type="button" onclick="moveForward('user')">forward</button>
<div>
<button type="button" onclick="setA()">A</button>
<button type="button" onclick="setB()">B</button>
<button type="button" onclick="setC()">C</button>
<button type="button" onclick="setD()">D</button>
<div>Your helper functions do not respect the caret position
Here is a version that uses delegation and data-attributes to not have inline event handlers
window.addEventListener('load', () => {
const elem = document.getElementById("user");
function insertCharAtCaret(char) {
var selection = getInputSelection(elem);
var startPos = selection.start;
var endPos = selection.end;
elem.value = elem.value.substring(0, startPos) + char + elem.value.substring(endPos);
// Set the caret position after the inserted character
elem.setSelectionRange(startPos + 1, startPos + 1);
elem.focus();
}
function setBack() {
var selection = getInputSelection(elem);
var startPos = selection.start;
var endPos = selection.end;
// Only proceed if there's something to delete
if (startPos > 0) {
// Remove the character before the caret or the selected text
elem.value = elem.value.substring(0, startPos - 1) + elem.value.substring(endPos);
// Set the caret position after the deletion
elem.setSelectionRange(startPos - 1, startPos - 1);
elem.focus();
}
}
function moveBack() {
var start = getInputSelection(elem).start - 1;
elem.setSelectionRange(start, start);
elem.focus();
}
function moveForward() {
var start = getInputSelection(elem).start + 1;
elem.setSelectionRange(start, start);
elem.focus();
}
// Delegation for character buttons
document.getElementById("buttonContainer").addEventListener("click", function(event) {
const tgt = event.target.closest('button');
if (!tgt || !tgt.dataset.char) return; // not a button or no char specified
insertCharAtCaret(tgt.dataset.char);
});
const actions = {
setBack,
moveBack,
moveForward,
};
document.getElementById("controlContainer").addEventListener("click", function(event) {
const tgt = event.target.closest('button');
if (!tgt || !tgt.dataset.action) return; // not a button or no action specified
const actionFunc = actions[tgt.dataset.action];
if (actionFunc) {
actionFunc();
}
});
function getInputSelection(el) {
var start = 0,
end = 0,
normalizedValue, range, textInputRange, len, endRange;
if (typeof el.selectionStart == "number" && typeof el.selectionEnd == "number") {
start = el.selectionStart;
end = el.selectionEnd;
} else {
range = document.selection.createRange();
if (range && range.parentElement() == el) {
len = el.value.length;
normalizedValue = el.value.replace(/\r\n/g, "\n");
textInputRange = el.createTextRange();
textInputRange.moveToBookmark(range.getBookmark());
endRange = el.createTextRange();
endRange.collapse(false);
if (textInputRange.compareEndPoints("StartToEnd", endRange) > -1) {
start = end = len;
} else {
start = -textInputRange.moveStart("character", -len);
start += normalizedValue.slice(0, start).split("\n").length - 1;
if (textInputRange.compareEndPoints("EndToEnd", endRange) > -1) {
end = len;
} else {
end = -textInputRange.moveEnd("character", -len);
end += normalizedValue.slice(0, end).split("\n").length - 1;
}
}
}
}
return {
start: start,
end: end
};
}
});<input id="user" type="text">
<div id="controlContainer">
<button type="button" data-action="setBack">backspace</button>
<button type="button" data-action="moveBack">back</button>
<button type="button" data-action="moveForward">forward</button>
</div>
<div id="buttonContainer">
<button type="button" data-char="A">A</button>
<button type="button" data-char="B">B</button>
<button type="button" data-char="C">C</button>
<button type="button" data-char="D">D</button>
</div>