In a form i have almost 20+ fields with value of Field ID having the pattern &qu

You can use a similar approach to what I posted here forum.appian.com/.../3518 on Dec 15, 2011.

If all your fields have an ID (given in the FORMS DESIGNER not in the DOM itself) that follows a naming convetion you can do something like this:

function toggleEnabledFlag(prefix,fieldsToDisableArray){
for(var i = 0; i < fieldsToDisableArray.length; i++){
var componentDom = window.Build.util.getComponentContainer(prefix + fieldsToDisableArray[i], window.FormDesigner.runtimeNamespace);
if (componentDom.length > 0) {
componentDom.get(0).disabled=true;
}
}
}

See how I "dynamically" build the ID of the component and I pass it to the getComponentContainer function. You can call this function in the load event of your form; assuming the text fields have an id of type: myfield1, myfield2, this is the way to disable these two fields:

toggleEnabledFlag("myField",new Array(1,2))