I created three textboxes.
<html lang="en">
<head>
<meta charset="UTF-8">
<meta http-equiv="X-UA-Compatible" content="IE=edge">
<meta name="viewport" content="width=device-width, initial-scale=1.0">
<script src="7.js"></script>
<title>Document</title>
</head>
<body>
<input type="text" name="" id="text1">
<input type="text" name="" id="text2">
<label for="color">Which cell to color</label>
<input type="text" name="" id="color">
<input type="button" value="Generate" onclick="h()">
<br>
<!--javascript code-->
<script>
function h(){
var a=document.getElementById("text1").value;
var b=document.getElementById("text2").value;
var col=document.getElementById("color").value;
var g=parseInt(col);
document.write("<table border='1'>");
var c=1;
for(i=0;i<a;i++)
{
document.write("<tr>");
for(j=0;j<b;j++)
{
document.write("<td>",c++,"</td>");
}
document.write("</tr>");
}
document.write("</table>");
}
</script>
</body>
</html>
<html lang="en">
<head>
<meta charset="UTF-8">
<meta http-equiv="X-UA-Compatible" content="IE=edge">
<meta name="viewport" content="width=device-width, initial-scale=1.0">
<script src="7.js"></script>
<title>Document</title>
</head>
<body>
<input type="text" name="" id="text1">
<input type="text" name="" id="text2">
<label for="color">Which cell to color</label>
<input type="text" name="" id="color">
<input type="button" value="Generate" onclick="h()">
<br>
<!--javascript code-->
<script>
function h() {
var a = document.getElementById("text1").value;
var b = document.getElementById("text2").value;
var col = document.getElementById("color").value;
var g = parseInt(col);
document.write("<table border='1'>");
var c = 1;
for (i = 0; i < a; i++) {
document.write("<tr>");
for (j = 0; j < b; j++) {
if (parseInt(col) == c) {
console.log(col)
document.write("<td style='background-color: yellow;'>", c++, "</td>");
} else {
document.write("<td>", c++, "</td>");
}
}
document.write("</tr>");
}
document.write("</table>");
}
</script>
</body>
</html>set background of all td nth possition
<html lang="en">
<head>
<meta charset="UTF-8">
<meta http-equiv="X-UA-Compatible" content="IE=edge">
<meta name="viewport" content="width=device-width, initial-scale=1.0">
<script src="7.js"></script>
<title>Document</title>
</head>
<body>
<input type="text" name="" id="text1">
<input type="text" name="" id="text2">
<label for="color">Which cell to color</label>
<input type="text" name="" id="color">
<input type="button" value="Generate" onclick="h()">
<br>
<!--javascript code-->
<script>
function h(){
var a=document.getElementById("text1").value;
var b=document.getElementById("text2").value;
var col=document.getElementById("color").value;
var g=parseInt(col);
document.write("<table border='1'>");
var c=1;
for(i=0;i<a;i++){
document.write("<tr>");
for(j=0;j<b;j++){
var background = '';
if(g == j){
background = 'style="background-color:red"';
}
document.write("<td "+background+">",c++,"</td>");
}
document.write("</tr>");
}
document.write("</table>");
}
</script>
</body>
</html>