My JavaScript function works fine, but I have problems getting different ids from the PHP input box.
window.onload = function()
{   
new JsD         
        
It's most likely with JsDatePick widget. Its target parameter takes a single ID of an element, therefore you'd have to wrap the JS code in a loop and initiate a separate instance of the widget for each field ID.
Assuming your input field indexing starts with 1:
window.onload = function()
{   
    var i = =$totalNumberOfInputs;?>
    for(j=1;j<=i;j++) {  
        new JsDatePick({
            useMode:2,
            target:"inputField" + j, //HERE I WOULD LIKE TO PASS DIFFERENT ID ex. "inputField1" + j
            dateFormat:"%Y-%M-%d",
            yearsRange:[1978,2120],
            limitToToday:false,
            cellColorScheme:"beige",
            imgPath:"main/img/",
            weekStartDay:1
        });
    }
}
You don't need to put the + sign to concatenate strings within double quotes (it's dot, by the way).