Question

I need to call a function by clicking a button. The button is on an aspx page and the function is on a .js page.
This is the code I use for my button:

<asp:LinkButton ID="lnkBTNSubmit" runat="server" CssClass="buttonlink" 
 OnClick="lnkBTNSubmit_Click" OnClientClick="onBtnSubmitClick();">Submit</asp:LinkButton>

and this is my function:

function onBtnSubmitClick() {
    var startDate = document.getElementById('<%= txtATrendStartDate.ClientID %>').value;
    var endDate = document.getElementById('<%= txtATrendEndDate.ClientID %>').value;
    checkDateRange(startDate, endDate);
}

function checkDateRange(start, end) {

    // Parse the entries
    var startDate = Date.parse(start);
    var endDate = Date.parse(end);
    // Make sure they are valid
    if (isNaN(startDate)) {
        alert("The start date provided is not valid, please enter a valid date.");
        return false;
    }
    if (isNaN(endDate)) {
        alert("The end date provided is not valid, please enter a valid date.");
        return false;
    }
    // Check the date range, 86400000 is the number of milliseconds in one day
    var difference = (endDate - startDate) / (86400000 * 7);
    if (difference < 0) {
        alert("The start date must come before the end date.");
        return false;
    }

    return true;
}

Please note that the function is on an another .js page.

Answer 1

To call the function in the other js file you have to include a reference to the js file on your page.

Example:

Put this in your head tag:

"script src="SomeOtherJSFIle.js" type="text/javascript"/script"