How to get min and max number from selected rows of table?

This refers to my previous question.

How to highlight/color multiple rows on selection?

<table id="toppings" border="1" cellpadding="2">
<tr id="id1">
<td>3</td>
<td>row12</td>
<td>row13</td>
</tr>
<tr id="id2">
<td>12</td>
<td>row22</td>
<td>row23</td>
</tr>
<tr id="id3">
<td>15</td>
<td>row32</td>
<td>row33</td>
</tr>
<tr id="id4">
<td>22</td>
<td>row42</td>
<td>row43</td>
</tr>
<tr id="id5">
<td>23</td>
<td>row52</td>
<td>row53</td>
</tr>
<tr id="id6">
<td>55</td>
<td>row62</td>
<td>row63</td>
</tr>
</table>


Javascript Code:

//Get list of rows in the table
var table = document.getElementById("toppings");
var rows = table.getElementsByTagName("tr");

var selectedRow;

//Row callback; reset the previously selected row and select the new one
function SelectRow(row) {
if (selectedRow !== undefined) {
selectedRow.style.background = "#d8da3d";
}
selectedRow = row;
selectedRow.style.background = "white";
}

//Attach this callback to all rows
for (var i = 0; i < rows.length; i++) {
var idx = i;
rows[idx].addEventListener("click", function(){SelectRow(rows[idx])});
}


But this time I have added an event to table for row selection and trying to get min and max value from selected rows (first column). Like above table, if I select middle four rows, i should get min = 12 and max = 23. How can this be implemented?

1 Answer
1

You can have two functions. I show the getMinValueExample().

function getMinValueExample(rows){
var minValue = null;
for (var i = 0; i < rows.length; i++){
var firstTd = rows[i].getElementsByTagName('td')[0];
var currentValue = parseInt(firstTd.innerHTML);
if(minValue == null || minValue > currentValue)
minValue = currentValue;
}
return minValue;
}


(not test so can contain some type errors but you should get the idea)
So if you call this after you've declared rows it returns the min value.
And if you call this one you get the max value

function getMaxValueExample(rows){
var maxValue = null;
for (var i = 0; i < rows.length; i++){
var firstTd = rows[i].getElementsByTagName('td')[0];
var currentValue = parseInt(firstTd.innerHTML);
if(maxValue == null || maxValue < currentValue)
maxValue = currentValue;
}
return maxValue;
}


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