Скачать или смотреть Limiting number of selection user can check from a group based on associated value of each checkbox

We can restrict or fix one upper limit for the user to select checkboxes from a set of checkboxes based on the value associated with the checkboxes. The total value will be calculated based on the user selection and selection is limited to a upper limit or sum of values.
https://www.plus2net.com/javascript_t...
User is allowed to select any number of checkboxes but sum of the values should not exceed a limit. Each checkbox has one numeric value associated to it.
After reaching upper limit, user can unselect any selection and go for selecting others but the upper limit will be maintained.
All checkbox will have common name and onClick event of the checkbox will trigger one JavaScript function chkcontrol(). This function will also receive the last selected number of the checkbox.
Inside this function we will first read the value associated with all the selected checkboxes. For this first we will read the status of the checkbox, if it is selected then we will add the value of the checkbox to our total. Note that while adding we have to use parseInt() to convert string to number.
Once we come to know the sum of all values of selected checkboxes, we will use one if condition to check the sum against our limit. If it is more then we will display one message saying the upper limit is reached.
if(document.form1.ckb[i].checked){
sum = sum + parseInt(document.form1.ckb[i].value);
}

After knowing the sum of all selection values we will use one if condition to check the value and if it is more than our set limit then we will display one alert box asking the user to restrict the number of selection to our set limit.
Now we have to uncheck the last selection by user by using the parameter we received ( j ) as input to the function. This is required as we are not in a position to exceed our limit. We will use checked property of the checkbox to unselect it.
document.form1.ckb[j].checked = false
#checkboxvaluelimit #maximumselectionvalue #restrictvalueselect