salesforce - Send with DocuSign custom button with validation -

Here's some God's help (sorry still is new to code) though I know that this is possible because I have some such work clues.

Essentially, I want to create a custom button to send with the document button at an opportunity which first ensures that all the minimum criteria are met. For this I know that I will need a VisualForce page which displays an error message, an Apex square and or custom button.

Many custom fields on the spot

These are related products with opportunity

There < Every time the button is clicked, these criteria are seen and any error is displayed, only the user has found all the criteria.

Can anyone help?

Apex Class

  Public class ReadyforDocuSignValidation {Public ID Opportunities {Get; Set;} public string error {get; Set;} public string raffle {get; Set;} Public Boolean Ster [Received; Set;} public string strorm [get; Set;} Public Ready ForDocuSignValidation (ApexPages.StandardController Controller) {sterr = false; Sterrmsg = 'You must play a contact role to send through Doku sign'; Error = 'Complete the following fields before conversion: & lt; Br / & gt; '; Theft = ''; Opportunitybozid = ((Opportunity Controller) Gaterekar ()). Id; Opportunity opportobj = [Select TOB_Billing_Entity__c, Split_Date_1__c, Split_1__c, is_This_Include_recurring__c from opportunity where id =: Opportunities]; If (opportunityobj.TOB_Billing_Entity__c == null || opportunityobj.Split_Date_1__c == null || opportunityobj.Split_1__c == null || opportunityobj.Does_This_Include_Recurring__c == NULL) {reft = '1'; If (opportunityobj.TOB_Billing_Entity__c == NULL) {error = error + '- TOB billing unit / & gt;';} if (opportunityobj.Split_Date_1__c == NULL) {error = error + '- different dates / & gt;'; } if (Opportobj.Split_1__c == nULL) {error = error + '- Split% / & gt;';} if (Avsrbojkdops_in_snt_rekyuring__ C null ==) {error = error + '- recurring product? / & Gt; ';}} If (opportunityobj.Stage! =' Ready for doctor ') {// sterr = true; If (empty == '1') {sterr = true; } Else {error = ''; Blank = '1'; Sterr = true; }}}}  

Visualforce page

  & lt; Supreme: Page standardController = "Opportunities" showheader = "false" extension = "ReadyforDocuSignValidation" & gt; & Lt; Style & gt; H2 {width: 300%! Important; } & Lt; / Style & gt; & Lt; Script & gt; Window.onload = function () {window.onblur = function () {window.close (); } If (document.getElementById ('sd'). InnerHTML == "") {var ids = document.getElementById ('id'). InnerHTML; Window.opener.location.href = "/ apex / docusign_editenvelope? Dsid =" + id + "& rc = & sourceID =" + id; Window.top.close (); } And {settimeout (function () {winndow.close ();}, 10000); }}; & Lt; / Script & gt; & Lt; Div id = "sd" style = "display": "& gt; {! Reft}  gt; id =" id "style =" display: none; "& Gt; {! Avsrbojid} & lt; / div & gt; & lt; sc: pageBlock title =" ReadyforDocuSign "& gt; & lt; sc: pageBlockButtons location =" down "& gt; & lt; button onclick = "window.close ();" & gt; off & lt; / button and gt; & lt; / Supreme: pageBlockButtons & gt; & lt; sc: pageMessage severity = "error" force = "1" & gt; & Lt; Supreme: outputText value = "{! Error} "escape =" false "/>  

Button

  Derequisition "id" for ur url = "/ apex / read"; Occupancy Id} "var width =" 350 "; var height =" 350 "; window.open (url, '', 'scrollbars = no, resizable = no, status = no, toolbar = no, menubar = no, width =' + Width + ', height =' + height + ', left =' + ((window winner width - / width) + ', up =' + ((height height - / height) / 2));