I am not able to select checkbox which has id="check stage<lead>" in jQuery Selector.
HTML:
<input id="check stage<lead>" type="checkbox" title="Select/Unselect Column" name="chk-stage-column-select" value="" onchange="">
Javascript:
// escape jquery selectors
    function jQueryEscape(str) {
        if (str)
            return str.replace(/([ #;?%&,.+*<>~\':"!^$[\]()=>|\/@])/g, '\\$1');
        return str;
    }
      var StageName = "<lead>";
  $("[id='check stage" + jQueryEscape(StageName) + "']").prop("checked", true);
Equivalent JsFiddle : https://jsfiddle.net/vuw43uav/5/
Note: I'm using jQuery 1.7 and we can select id with spaces in jQuery. refer this jsFiddle: https://jsfiddle.net/vuw43uav/7/
 
     
    