SharePoint field required on task form - sharepoint-2013

Question

I have a task form (OOB) where user needs to enter comments only when clicks on rejected button.
I wrote following script but this is firing even when clicked on approved button.
$('input[value=Rejected]').click(function() {
PreSaveAction();
});
});
function PreSaveAction()
{
var commentsBox = getFieldControl('ApprovalComments','Text');
var comments=$("textarea[title='ApprovalComments']").val();
if(comments.length==0)
{
var errorHtml='';
errorHtml = '<span class="ms-formvalidation"><span role="alert">Please enter Comments<br></span> </span>';
commentsBox.after(errorHtml);
return false;
}
return false;
}
function getFieldControl(fieldName,fieldType)
{
var control = $('[id^=' + fieldName + '_][id$=' + fieldType + 'Field]');
return control;
}
Thanks in advance

Answer 1

You can actually achieve it easily. Below is the jquery code sample:
function PreSaveAction()
{
var currentPage = decodeURIComponent(window.location.href.replace(/\+/g, " "));
if (currentPage.contains("Lists/WorkflowTasks/EditForm.aspx"))
{
var commentsTextArea=$("textarea[title='ApprovalComments']");
if(commentsTextArea.val().trim()=="")
{
var errorHtml='';
errorHtml = '<span class="ms-formvalidation"><span role="alert">Please enter Comments<br></span></span>';
commentsTextArea.after(errorHtml);
return false;
}
else
{
return true;
}
}else
{
return true;
}
}
String.prototype.contains = function (it) {
return this.indexOf(it) != -1;
};
Explanation:
PreSaveAction method will be triggered in all the New and Edit Forms in SP2010/SP2013.
Hence there is no need of Button onClick methods for client side validation on these forms.
In the above code, when you click of Save/Approved/Rejected buttons in your page, PreSaveAction will be fired.
We will be checking if current page is of Task Forms (WorkflowTasks is the name of the task List , please update this accordingly), else return true.
If the ApprovalComments is empty then error message will be shown and return false.
Else, return true.
Also notice the helper method String.prototype.contains.